There are several synonyms for the phrase "be willing to purchase." Some of these include "be ready to buy," "be inclined to acquire," "be prepared to procure," and "be disposed to obtain." These phrases all convey the same general meaning of being open and willing to make a purchase. Other possible synonyms might include "be interested in purchasing," "be eager to buy," or simply "be willing to acquire." Depending on the context, certain synonyms may be more appropriate than others, but these various phrases can all be useful in helping to convey the same underlying message.