Your best bet is regular canning jars. You can buy new if you can't find them used. Put a ad up on craigslist. Wanted canning jars Somebody might give you some free ones. If you get a email that someone wants to sell them, ask them their price. Don't offer a price first. They might be lower than what you would offer.
About half of new is a fair price to pay for used jars.
I sold some last year on craigslist for $ 4 a dozen.
Check thrift stores and garage sales. Put the word out to friends/family if they know anyone who might want to get rid of canning items.
Start looking now for canning lids. Buy a few dz, a week so when you do start canning, you don't have to buy in huge quanity all at once.
Okay, the store jars you have that maybe pickles came in. You probably can get them to seal again. But it is taking a chance. I use different size glass jars that are not canning jars, to store dry goods in. I been thinking of reusing the jars that gravy came in, but it would be for jam, and it would go in the frig even if I thought I had a good seal. That way I can give a few away and not worry about getting a good canning jar back.
Old mayonaise jars still work good. Suggestion would be to use them in a water bath. Not in a pressure canner.
Years ago, there used to be a brand of coffee that came in a nice slender jar that if you used a 63 lid on, you got a good seal. I don't think, they make this size lid anymore. Most lids are regular and wide mouth size. 63's were smaller than regular and last I knew, made back in the 1970's. I happen to have a gallon size ziplock bag of them, that I found at a garage sale last year. I'm hanging onto them for emergency back ups. And yes I have the old jars to fit them on. I rescued them out of a cellar because the 90 yr old lady said she was done canning and gave them to me. I have to go back this spring, and get the balance of the jars. She had 3 outside walls full of canning jars.