My boyfriend wants me to go on vacation with him?

My bf is going out of town and he told me his mom wanted me to come but one day I overheard her talking to him and she said she didn't really want me to but shes letting me come because he said he wouldnt come if I didnt go she also said I would have to pay for my food.i work but I really dont have to miney to pay for dinner every night im 17 and I have to pay bills he also said we might go to seaworld and if I paid for my ticket and dinner I would be broke.he doesnt know I over heard them.idk I know my bf ilntends on buying my dinner and stuff because she said that but he just got out of debt and I dont want him spending unnessicarly on me even though he already doesspend alot of money on me but when ur on vacation u spend way more than usual should I go even though its going to hurt me financially or should I stay ?my mom doesnt want me to go if I have to pay because she thinks if ur invited than u shouldnt have to pay I need some advice what should I do?