This is a problem we always seem to struggle with...finding a way to display artwork without paying huge amounts of money for framing. Since the type of framing we choose usually depends on the artwork, we're always having to come up with new solutions to the problem. Along the way, we've found a few cheap frames that we keep coming back to.
Sources for Cheap Frames:
With frequent sales on top of already good prices, craft stores like Michaels are a good bet for affordable frames. We're partial to the basic Studio Décor® Belmont line which comes in several colors including white, black, red and teal in several sizes, all under $20.
Poster Hanger by Jorgen Moller
This is a great solution for a collection of posters, although it doesn't protect the artwork under glass. We like the look for small-scale pieces, but when you go big the artwork can resemble a hanging slideshow screen. $16.95 - $79.95, depending on size (12" - 72")
The in-store offerings can be hit or miss depending on inventory and demand (especially when college students head back to school), but you'll find a variety of affordable frames you can order online. We especially like that you can filter by frame size to find just what you're looking for. The best deals are the poster frames for $9-10.
You probably think of Zara as just a clothing store but they have a robust home goods selection online. The frames in their collection are smaller, tabletop frames, but the prices are good and so is the style factor. We especially like these clear plastic "frameless" ones ($25-50).
Although they top out at 16" x 20", Wayfair has a nice selection of inexpensive but attractive wood hanging frames most in the $20-40 range.
Their selection is mostly framed art prints for the home, but if you want to frame your albums or other square art work, they offer cheap square 12" x 12" frames in silver or black for about $15.