Yeah ask him to go with you, by yourself and splitting the cost is a good idea. The two of you are friends there is no reason why you shouldn't be able to enjoy each others company, unless you're thinking of someone else while you're together. Don't let this be a mercy date for either of you, make sure that the two of you can really have fun. It's not necessary to be open to other possibilities.\n\nEnjoy the Prom!