One thing that's made a big difference for me is that I plan my painting size in advance so that I know my painting will fit into a particular size of mat and frame. (No oddball sizes!). This allows me to remove paintings from frames, and put a new painting in the same frame or mat. Recycle, reuse! As you can see from the Framing Matting Sizes For Artwork.pdf document at the end of this blog post, I use a limited number of sizes for my works on paper and I rarely deviate from those dimensions. That saves me money and time.
Next, I've gotten to the point in my life where cutting matboard with a mat cutter is too much of a strain on my hands, so I order custom cut mats in bulk (it reduces the price dramatically!) from a website called www.matboardandmore. They ship the mats in sturdy boxes and I keep the mats boxed up and protected in my garage. They also carry foamcore backing board cut to the size of your mat (much easier than buying a huge foamcore board and trying to cut it yourself--something I used to do but don't anymore). I favor a single 4 ply off white (or white) mat because most shows I enter request this type of mat, and it's easy to order this in bulk.
I favor black matte (not shiny) metal frames which I order from www.americanframe.com. This company makes a good product, and ships the frame sections in plastic sleeves with size printed on an attached label, and includes a frame kit for assembling the frame so that all you need is a screwdriver. Why do I favor matte black metal frames, you ask? It's simple--when you have to put together a big solo show (as I'm currently doing) it's best to have your frames present a unified front! As always, one must read a show's prospectus--there are organizations that insist on non-metal frames (which puts an additional cost burden on the artist, who may have to take the painting to a frame shop).
I used to order my plexiglass from American Frame but shipping has gotten expensive for bulky items, so I was happy to discover Tap Plastics https://www.tapplastics.com/ which has a local store in Portland, Oregon, where I live. I can call ahead and place an order over the phone for whatever size I need of their 1/8" acrylic plexiglass and pick it up the next day. Plexiglass scratches easily, so they apply a thin plastic film on both sides of the plexi which you keep in place until you are ready to assemble your frame--it peels off with very little effort. I often order extra sheets of plexi in the sizes I frequent use because sometimes my painting comes back from a show with scratch on it, rendering it unusable for future paintings.
The other items you'll need to put the painting together in the frame are linen hinge tape (instructions for using this are in the Framing Made Simple by Ellen Fountain .pdf I've attached) and plastic coated hanging wire (I put a link in the Framing For American Frame .pdf). And of course a screwdriver--I have an electric one with interchangeable flat/phillip heads. Automation is our friend!
I hope this post gives artists the courage to do a little DIY matting and framing. Here's another tip: Don't feel you have to do it ALL by yourself. When I recently needed to assemble 14 paintings in their frames for an upcoming solo show, I hired a 30 year old helper (the son of an artist friend) to come over and assist me with the task. It took the two of us working together about 3 hours to assemble 14 paintings. (I had previously taped the paintings to the mats and ordered all the right sizes of plexiglass and metal frames, so I was organized and ready!). This young man hadn't framed paintings before, but after I demonstrated the process (and stayed nearby to help with any questions) he got the hang of it. 20 years ago, I could have easily done this task myself, but I'm learning that hiring an extra pair of hands is money well spent. It's still less expensive than farming the whole thing out to a frame shop.