Thanks to all those recommending Frame Destination, as the owner I greatly appreciate it. As long as you take a little time to learn a little about framing you can avoid the cost of a custom frame shop by doing the design, picture mounting and final assembly yourself. The least expensive picture frames are those manufactured in bulk overseas and imported in volume. They will have a narrow size selection and are not likely to be good for long term protection of the print, that is where companies like mine and other online wholesale companies come in. We manufacture in the US so our costs are higher. You can take on additional labor by doing even more work yourself such as cutting the mats, backing and or actually cutting and joining the frame moulding. This option requires the purchase of equipment. The more you pay for the equipment the more labor your save.
You can consider the picture frames to be an investment and you can change the pictures out. Even if you dry mount your images you have to change the backing. If you are t-hinging or use photo corners you can just change the picture. Do you think you will ever do another showing? Do you plan to sell framed prints? If you do, you can eventually get your money back on the frames.
Regardless of how you decide to display your images, full frames, gallery wraps, or gatorfoam, be sure to look for volume discounts. Many companies offer those, and on matboard the volume discounts are steep. In fact, if you buy cut mats from a company like mine at qty 25 your price will be close to the cost of buying sheets from a distributor and cutting them yourself. Dont forget to look into the shipping costs.