I agree-it's actually good that you recognize this
Definitely if you don't have a dog house-and I understand that cost is huge-bring him in. Dogs can be easily contained in a dog proof room. A bedroom with nothing accessible-or a bathroom, or kitchen etc
The other option as Fawkese pointed out-Craigslist or Kijiji -you can find decent used items on them for cheap
Treats-like Fawkese said kibble works too. In fact a lot of 'dog treats' are flavored cardboard with a bunch of chemicals.
Cheap treats that you already have, and are actually healthier: dog kibble, peices of cheese, peices of meat, yogurt, bread, hotdogs (slice them and microwave for a crunchy treat).
And toys-well

Dollar store stuffed toys and balls-very cheap. Also baby toys at the dollar store...and y ou might like this thread :
Home made/household item dog toys?
The BIGGEST thing I'm going to recommend that you do is get pet insurance. Vet bills-especially emergency vet bills can put anyone in the poor house. It's the easiest way to make sure your covered. And some of them even cover regular check ups, vaccinations and the like. You can customize most of them to cover what you like and you can generally choose packages via the monthly cost-which is very low and affordable-cheaper then you pay for internet I'd wager

It's very important if you are strapped for cash, or really-for ANYONE-to have pet insurance. I heard VPI is a good company but I'm not very familiar with them in the US-so it would be something for you to research-and I'd highly highly recommend doing so