Do I have bad luck with guinea pigs?

I recently bought a guinea pig from petco that had ring worm so I took her back and got another who looks like it has an eye infection and I adopted another who has crusty eyes and breaths harshly he doesn't really wheeze but his nose is runny grrrr I don't have the money to take them to the vet until this weekend but I know caveys can get really bad uri really fast please should I just give them to better homes I have never had suck bad luck with animals despite the large amount i have had