1. While trying to modify as little as possible, how can I make the bilateral sales contract in Practical Example 1 unilateral?
2. What if I copy and paste Practical Example 2 and modify like it this?



> 
> ~~Daniel~~ [Alex] offers (or promises) ~~a free watch~~ [a bicycle] to anyone who ~~three tokens from the packets of cereal he manufactures, together with a cheque for £5~~ [pays him £150]. 
> 
> 
> 


But then doesn't my edit become a bilateral contract? 


Poole, Shaw-Mellors. [*Contract Law Concentrate* (4 ed 2019)](https://www.amazon.co.uk/Contract-Law-Concentrate-Jill-Pool/dp/0198840446/ref=dp_ob_title_bk). p 5.



> 
> The key distinction: bilateral and unilateral agreements
> ========================================================
> 
> 
> Broadly, agreements will be one of two types:
>  • bilateral
>  • unilateral.
> 
> 
> Definition
> ----------
> 
> 
> **Bilateral agreements:** by far the most common in practice and consist of a promise in
>  exchange for a promise. Bilateral means both parties are bound on the exchange of promises,
>  although there has yet to be any performance of those promises.  
> 
>        A typical sale of goods agreement is bilateral. 
> 
> 
> ### Practical example 1
> 
> 
> Alex offers (or promises) to sell his bicycle to Becky for £150 and Becky accepts, thereby promising
>  to pay £150. (We will use this as our example of a bilateral agreement and look at variations and additions
>  to the facts throughout this chapter.)
> 
> 
> Definition
> ----------
> 
> 
> **Unilateral agreements:** consist of a promise in exchange for an act. It follows that only one party is
>  bound at the outset by a promise. The other’s acceptance is the performance of the requested act.  
> 
>        For example, a typical unilateral agreement will involve an offer of a reward and may be
>  phrased as an ‘if’ contract: I promise to pay £50 to anyone who finds and returns my lost dog.
> 
> 
> ### Practical example 2
> 
> 
> Daniel offers (or promises) a free watch to anyone who returns three tokens from the packets of
>  cereal he manufactures, together with a cheque for £5. Emily accepts by returning the three tokens
>  with her cheque for £5. (We will use this as our example of a unilateral agreement and return to this
>  example later in the chapter.)
> 
> 
> 


p 6.



> 
> Making the correct distinction.
> -------------------------------
> 
> 
> It is not possible to accept a unilateral offer by promising to
>  find and return the lost dog or by promising to collect and return the tokens and the cheque. By
>  comparison, the agreement to sell the bicycle cannot be unilateral. Students sometimes suggest
>  that a simple sale contract is unilateral by interpreting the act of paying for the bicycle as the
>  requested act. This is incorrect since, as long as it is possible to accept by promising to buy (which
>  it is in the example), the agreement will be bilateral.
> 
> 
> 



What's the tiniest modification necessary to convert a bilateral, to unilateral, sales contract?