Hi I Have A Rat Terrier And For Quite Sometime

Hi I have a rat terrier and for quite sometime he has been having some health issues, but within the past year I noticed a change to where it is more frequent, he throws up immediately after drinking water, seems like he is having these asma breathing type attacks, eats wrongful things, eats dirt, and he can't seem to get enough water, his teeth have mostly fallen out and his mouth is basically rotten, and teeth are bad, i looked online and not sure about what i found, I am going to try to take him to the vet but short on money for it, i feel really bad because i don't really have the money and not sure about what to do, i hope the vet will understand, i plan to just take him and get him treated and see if they will work with me afterwards i hope. Well let me know if this