im in the UK and get my contraceptive pill for free on the NHS.

but if i had to pay about £50 every however often for contraception i would discuss splitting it with my partner... particularly as you BOTH have issues with other methods..
he's not having to buy condoms which would probably be one of the easier/cheaper methods so whatever method you have both settled on .. which happens to be something for you.. you should contribute equally.

Particularly if you're not quite as well off financially as him.

that, or maybe look into cheaper options that might work for you?

i know there are options with condoms .. he may be allergic to the latex or the spermicide.. so it might be worth looking at latex free ones. i think if its a reaction to spermicide you need to look for some WITHOUT nonoxynol-9 or 11.