Why not just wait for your chance to buy ETH so you won't pay interest?
It's just a few more days to go so I think your developer can patiently wait for that.
Unless.....
I can't delay immediate gratification my boy.
Then offer a valid collateral my boy.
You just started a project, not anticipating you will be lack of funds to pay your developer? You should be prepared for that.
Again, unless......