What are the most effective ways for a small business to start marketing with little or no budget?

Leveraging your product. Use a word of mouth. Very important is believe in your product that you are going to leverage.

Hi Sir

Because if high cost is paid you may face failure in your outcome expected, by another means you should plan as your income shows to you & about your product segment

The best way for a small business to start marketing is by using profissional Social Media; such as Instegram, Facebook and Twitter. Another great effective way is to use google ads which will guarantee a flow with a very low marketing budget. With all of that we cannot for get the power of the word of mouth marketing through great services (Some times it will call for Free services as well) 

You can use social media like facebook to create a page to reach your customer base, offering samples to general public to create a buzz, handing out pamphlets to passers walking by and busy areas known for extensive traffic passing through these are a few of the many avenues you can use which cost very little to nothing to accomplish, word of mouth also helps a tremendous amount.

In this digital age much of the marketing is done online. A word of mouth can be spread through online forums usually. Facebook/Instagram/twitter are cluttered with entertainment advertisement. In order to reach the people at your local vicinity one must find out what the active local forums are. A great place to start would be reddit, it is a global forum where one can seek help and support from local redditors. Once you get to know the local active members, one can easily use their help to influence their product in the local market. 

News spreads faster digitally than verbally these days.

It depends on your business.

I agree, that today social media channel is important, however it may not work for everyone as the main channel. So first of all you need to do your research on who is your customer. Then, depending on the service you are providing, decide on which channel will be more important, which will be just to support.

When you are a small business with limited resources (staff, time, money; but that's also right with big businesses) - don't forget the Pareto principle or 80/20 rule: 80% of effects will come from 20% of causes. Now, your goal will be to find that 20% and that depends on the business and its customers.

Just to give you few ideas of marketing possible with small businesses:

- WOMM (word of the mouth) and this one can go with "guerilla marketing" - let people talk about you, in a good way preferably ;) If you can offer your service for free to some people, close friends, etc and then they can talk to others, leave you a comment (eg. if you have restaurant - that would be on Tripadvisor; if something else - that could be Facebook or Google plus comment, etc). As for "guerrilla" thing - that would need to be something exceptional, that would go viral online and offline.

- Promos/discounts - you may not have money for big marketing, but you have your margin. Some businesses, when they start, go with the 5-15% discount for "new customers", in reality giving people a chance to try the product/service. Don't make people used to your discounts, though... They may not come back for normal price... But that can be included as your "marketing budget". Also, you can use it as a tool to find out which channel works for you: eg. you have a 5% discount with a code published in the local newspaper, and a 5% discount with a different code published in social media or on the flyers. After some time you see which one works better.

- Events: either participating in the event, or sponsoring the event (where "sponsoring" can be anything), or organizing an event... Imagine chef opening his new, small restaurant. Noone knows about it. Should he announce and pay for advertising it? Sure he can. But there are plenty of restaurants advertising. What if he advertises a workshop on cooking something? Or an event where people could try few dishes for a fixed price?  Etc, etc.

- Free entry - this one depends on the business even more. Could do with entertainment, food, some other services. Inviting press, tv, etc. to try and then talk about it. They receive plenty of these probably, but then think why you are so special and different and stand out.

- web advertising - if your customers use web - go web paid campaigns for some time: Facebook and AdWords. It can be overwhelming at the first glance, but the good thing is you can try with any budget you want. Some time to invest required, but then it would work with any money. Depending on the range and keywords, you can start from 1eur/5aed per day just to try (moreover - sometimes google gives free credit to first time users, so you can try without spending a penny). On the other hand - you need a website, to which the ads can lead people.

Hope that helps a bit.

Un programme de recommandation est un excellent moyen d’encourager les gens à devenir des défenseurs de votre marque, de votre produit ou de votre service. 

Un « MeetUp » est un événement informel et gratuit que toute petite entreprise ou organisation, ou tout petit groupe de personnes, peut organiser

Quora, Reddit, les groupes LinkedIn et les communautés Google+ ne sont que quelques exemples parmi les nombreux forums et groupes en ligne auxquels vous pouvez participer. Interagir avec ces communautés en ligne vous permet d’enrichir votre réseau en ligne et de créer de nouveaux prospects.

Use industry specific networking events to spread word of mouth and also spread the word through existing networks

As Social Media is currently the talk of the town, its the easiest & cost-effective way to start marketing with. Moreover, cold calls can make a big difference. 

assess what competence and equipment you already have that can help you get started without investment Be sure your idea presents a real opportunity Do not hire anyone until you get cash

However, if you want to start an activity that still requires a certain investment and you do not offer sufficient guarantees to your banker, you can:Find someone who has enough confidence in you to vouch for it.Contact Business Angels.Find partners

Ask for referrals from your current customers and friends. Give a speech about your product whenever an opportunity presents itself. Collaborate with others and network as much as possible. Build a free email list and put content on your blog.