It is not true that one can not enter into a legal contract with someone jobless or indigent.
The only issues regarding "capacity" to contract involve (1) age - must be a legal adult, (2) physical or mental state - must be legally competent, and (3) intoxication - may not be intoxicated to the point of incapacity at the time of contract formation. These three issues may affect the contract's validity.
The law freely allows parties to form contracts of virtually any kind, barring illegality.
The short answer is not true. If over 18 years of age and mentally competent is pretty much it, however if there was no meeting of the minds the contract may be voidable. Or in other words both parties did not understand the same things. To accuratly answer this question more facts would be helpful.
