"an agreement giving rise to obligations which are enforced or recognised by the law. The factor which distinguishes contractual from other legal obligations is that they are based on the agreement of contracting parties". (Trietel 2003)
"An expression of willingness to contract made with an intention (actual or apparent)that it shall become binding on the offerer as soon as it is accepted by the person to whom it is addressed..and an acceptance "is a final and unqualified acceptance of the terms of an offer."(Cracknel 2001).Because of the interaction of the offer and its acceptance a validly enforceable contract between Andrew and Billy has been formed.
Next, as the facts of the question state, right before Billy delivered the equipment Andrew changed his mind to having wireless enabled computers, and not the wired ones specified in the contract. He asked Billy to let him have the more expensive, wireless enabled computers rather than the ones they had agreed upon. The question which arises at this point is whether Billy can subsequently claim the extra 500. The courts are likely to view this 500 discount within the realm of the traditional definition of consideration , bearing the detriment/benefit dichotomy (Cracknell 2001).Consideration has been defined as " either some right ,interest ,profit, or benefit accruing to the one party or some forbearance ,detriment ,loss or responsibility given suffered or undertaken by the other".1
Andrew has offered Billy a practical monetary benefit which amounts to sufficient consideration to "close the deal"2. The court will not concern itself with the value of the consideration i.e. "consideration must be sufficient but not necessarily adequate"3.Therefore Billy cannot challenge the price of this transaction as it is up to him to go London as often as he likes and use the internet there for free at his caf. The waiver of fee in the internet caf is a monetary advantage no matter how inadequate it may seem in business terms and the courts will uphold this arrangement. Therefore in my opinion Billy will not be able to claim this 500 discount.
The Claim for 2000
Although Billy will not able to claim the 500 discount , but when Andrew asks Billy to accept 8,000 instead of 10,000 in full settlement, this becomes a case of breach of contract. The payment of 10000 was an express term of the contract and by his refusal to pay he is breaching the contract. This means there is a breach of contract because Billy has performed his part of the contract and Andrew is avoiding his performance i.e. the payment of 10000.Therefore Billy will be able to repudiate the contract and get back his equipment as well as damages for any depreciation in the value of the equipment as well as any wasted expenditure.4
However Andrew has not totally refused payment. He is offering a partial amount of the payment in settlement of the debt because he feels that he will have financial difficulties. Billy accepts this money fearing that Andrew is going bankrupt. The acceptance should technically mean that he should not be allowed to claim back his 2000 .In this regard I would