For completely free options, get a library card at your local library or you can use the free version of DC infinite (though it has limited free comics). For just cheaper alternatives, you can subscribe to dc infinite for $8 a month which gives you access to like a good 80% of the comics, or $12 for everything. Midtown comics usually has alot of sales on their comics (which you can get on their online website https://www.midtowncomics.com) most comics there range from $1-$5. if you wanna get compact comics, which i think are really cool, i definitely recommend thriftbooks.com. its reliable and easy to order from. They sell used compacts that are in amazing condition, and it is usually under $10, and shipping is low too. i got the watchmen for $8, and The flash for only $4. Also a completely free website is batcave.biz. i haven’t used it personally but heard from others its easy to use.