If you are on a budget i would suggest checking out the range of frames that Habitat produce. I've used their Aluminus metal frames for many of the product photography shots on this website.
Habitat stock frames have a modern look and are a high quality budget friendly option. I tend to go for a frame larger than the print as they look much better with the extra breathing space around them.
To achieve a gallery style finish i would use a bevel mount inside the frame. These can ordered online and cut to any size required. If you need assistance > Contact Studio. I'm happy to help you.
The most expensive option is custom framing. This is best if you want to create a real statement piece. Ask your framers about using a product called 'Art Glass' if you going down this route. It is far superior to standard glass and really enriches all the colours in the prints.