Sorry parley, I agree, don't mess about with splints - abscesses in paws can turn very nasty and need antibiotics to prevent that. If you're short on cash ring the vet and discuss it with them, they might let you pay later or work with a local charity who can loan or pay the vet directly.
Please don't do any DIY treatments or give the cat any medications without seeing a vet. If you suspect it is an abscess and not a broken bone you can bathe with warm salty water but that's it till you see a professional.