Given that you are severely undercapitalized, cutting your runway in half for a domain name makes no sense. Particularly since there will be plenty of domain names for sale in 3, 6, or 12 months when you are ready to bring the product to market - or have angel funding.
There is no point in spending money on something today which you don't need and may not need...Pivots happen.
There is no point in spending money on something today which you don't need and may not need...Pivots happen.
Good luck.