As per IFRS 15, the entity may need to estimate transaction prices. what are the methods used to estimate that?

(a) Adjusted market assessment approach

An entity could evaluate the market in which it sells goods or services and estimate the price that customers in that market would be willing to pay for those goods or services. That approach might also include referring to prices from the entity’s competitors for similar goods or services and adjusting those prices as necessary to reflect the entity’s costs and margins.

(b) Expected cost plus a margin approach

An entity could forecast its expected costs of satisfying a performance obligation and then add an appropriate margin for that good or service.

(c) Residual approach  

If the stand-alone selling price of a good or service is highly variable or uncertain, then an entity may estimate the stand-alone selling price by reference to the total transaction price less the sum of the observable stand-alone selling prices of other goods or services promised in the contract. A selling price is highly variable when an entity sells the same good or service to different customers (at or near the same time) for a broad range of amounts. A selling price is uncertain when an entity has not yet established a price for a good or service and the good or service has not previously been sold.