You may have only been on one date with your boyfriend in a 5 month relationship because he has taken you for granted and believes that he can get away with this kind of behavior.
Telling you that he doesn’t have much money is just an excuse. You have suggested dates that would be free or cheap and he has remained uninterested.
This kind of behavior would indicate that he doesn’t really value his relationship with you.
He may have reached a point where he believes that he can just keep getting his boyfriend privileges from you without having to give anything back in return.
Hence, it is best to stop or drastically cut back on the boyfriend privileges such as intimacy, constant accessibility and companionship, etc., that you have been giving him.
Take something away from him in order to get something that you want.
If you are to do this consistently, there is a good chance that he will start feeling deprived.
As long as you remain clear about what you expect from him as far as being taken out on dates, he may start making sure that he takes care of your needs just as much as you have been taking care of his needs over the course of the last 5 months.