Spend my money or his?

I don’t know what to do! My SO wants a new xbox for his birthday. It’ll be about $300. I literally only have like $600 till I get paid next Friday. I have no bills to pay though. He gave me $300.

Should I pay for half and get him other little gifts like a bottle of scotch, a game maybe, and some other things. Or pay for the whole thing?

Would it mean less if I only paid half?

I meant that I would give him his $300 back and then pay the rest so I would have $300 for the week