As I may have mentioned, my bedroom is undergoing a much-needed makeover. New bedding is en route, and while I couldn't be more excited about it, there's a tiny issue: my dresser drawer knobs will no longer go with the room.
1&2 Etsy, of course! Though you have to slog through the listings because most sellers bundle and you can't search per unit pricing, it's generally worth it as you have great vintage and handmade options that will make your cabinet unique. Also, there's usually only 1 or 2 of something, so if you want to redo your kitchen in matching knobs, you may be out of luck.
3-6 Hardware specialty websites. Tons of selection under $5, and while most options aren't particularly exciting, you can find some gems. Also great for specific searches, buying in multiples, and free shipping with a minimum order.
7&8 Overstock.com. Inexpensive and $2.95 shipping. Some fun options, though as with most Overstock purchases, they're bundled, so this isn't the site to to go if you only want to buy 1 or 2.
9 Target. I didn't expect Target to have any viable options for me, but their line of acrylic knobs are pretty cute and come in a variety of colors. Bonus for being able to go to a store and look at them before you buy!
10 IKEA. Oh, IKEA! You can't beat the prices. At $.33 a knob, you could go crazy and redo all the hardware in your house.