Up to a certain size, mating and framing is an easy enough DIY project. 12x18 should be fine with minimal gear. Unless you have a bad case of the shakes.
As I said in a recent thread here, I do all of my own framing and one thing I will not do is dry mount the print. I only remember one of the reasons why it is not a good idea and that is that prints (just like any other paper) need to breathe, meaning they expand and contract with the seasons. But to be honest it is so easy to mat without dry mounting that I can't even imagine any reason to dry mount.
There are only 3 things you will need to mat a print: acid free mat board, acid free tape and a mat cutter. Acid free is very important as products that are not will eventually transmit the acids to the print and ruin it. A good source of mat board is your local frame shop. I have always gotten mine from a frame shop that works with artists because they have no problem understanding you want to cut your own mats. But any frame shop could sell you the stuff. I would stay away from craft stores though as I have more than once felt they had no idea what acid free meant...
If you don't have a frame shop around, the stuff is available on the web.
Now, cutting the mat requires a mat cutter. This is the one I started with and it works great up to a certain size. When I started cutting bigger mats I went to a heavier duty model because my cutting lines were not straight
Handheld Mat Cutters: Deluxe Pull Style
My heavy duty cutter is also from Logan but this one did me fine for years. I also made it a present to friends a number of times and most of them are still in use.
Framing is a different animal all together. Most of the time I like simple frames and aluminum section frames (found at all craft stores) did me just fine. Other times I wanted a fancy frame and I found those at auctions. As long as it was big enough for a photo I bought. Most framed work sold for a dollar or 2 at the auctions I attended (in MD, btw) and I bought section frames too... Since I cut my own mats it was easy enough to make them fit the frame.
Hope this helps and inspires you. If you have any questions, don't hesitate to ask.