This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
If A and B attempt to enter into a contract and such contract is unenforceable because it is vague and indefinite, either party who has paid money, furnished goods, or rendered services under such contract, may recover the reasonable value thereof from the party to whom they were furnished.1. A contract by which A is to pay to B, "a fair share of the proceeds," is uncertain; and no action can be brought for damages for its breach, but reasonable compensation for the value of such services may be recovered.2 Where A acted as body servant and nurse for B for several years, and B without making any express contract for paying A any certain amount of wages, had promised to provide for him handsomely, A was allowed to recover a reasonable compensation for work done by him for B.3 If A renders services to B under a contract by which B is to pay A for such services by making a will in his favor and such contract is so vague that it can not be enforced, A may recover reasonable compensation for such services.4 If a building is erected under a supposed contract which proves to be invalid, since the architect who prepared the contract inserted different amounts in the alleged duplicates, one of which he delivered to the owner and the other of which he delivered to the contractor, the contractor may recover reasonable compensation for work and labor under such contract.5
Where some of the terms of the contract are definite, this principle merges into the principle that in the absence of a specific agreement as to price, time, and the like, it will be understood that the parties intended a reasonable price, a reasonable time, and the like.6 If a contract provides that A shall make an excavation and if it fixes the price at which certain classes of material shall be removed,, but is silent as to the price to be paid for other classes of material, the contractor may recover reasonable compensation for removing materials for which no specific provision was made.7 If an attorney renders services without any express agreement as to the amount of compensation therefor, he is entitled to recover a reasonable compensation for the work done.8 If children agree that one of them shall support their parent, but do not complete the contract by fixing the compensation which is to be paid, the child who supports such parent under such contract may recover reasonable compensation from the other children.9
1 Cooper v. Claxton, 122 Ga. 596, 50 S. E. 399 [apparently so held, though claim was barred by limitations]; Indianapolis Northern Traction Co. v. Brennan, 174 Ind. 1, 30 L. R. A. (N.S.) 85, 87 N. E. 215, 90 N. E. 65, 91 N. E. 503; Washington, B. & A. R. Co. v. Moss, 127 Md. 12, 96 Atl. 273; Varney v. Ditmars, 217 N. Y. 223, Ann. Cas. 1916B, 758, 111 N. E. 822.
2 Varney v. Ditmars, 217 N. Y. 223, Ann. Cas. 1916B, 758, 111 N. E. 822.
3 Ryans v. Haspes, 167. Mo. 342, 67 S. W. 285. In such action, sums of money given by B to A as gratuities can not be deducted from the amount which A should recover.
4 Cooper v. Claxton, 122 Ga. 596, 50 S. E. 399 [claim, however, barred by statute of limitations].
5 Vickery v. Ritchie, 202 Mass. 247, 26 L. R. A. CSS.) 810, 88 N. E. 835.
6 See Sec. 92 et seq.