Nothing beats building a relationship with a local frame shop... Pricing believe it or not is lower than the big box stores, and the quality is head and shoulders above that which you can put together from a prefab Michaels kit...
I collect cuts 3x5's and GPCs and typically frame them in the same fashion that you are describing... Some advice if you are going to put them together yourself:
1-Protect the autographs: put them in a lucite prior to affixing them to the matt board. This way you will not have any adhesive staining or potential damage to the autograph down the road if you want to remove it...
2-Try to use acid free board and backing: this doesn't really matter if you are protecting everything in lucite.
3-Use a dust cover (corrugated paper affixed to the back of the frame). this will preven dust and other particles from getting in the frame
4-Glass: anything uv protectant is better (but more costly)
If you have a standard size for the frames (11x14) and dimensions of your matt cut, you definitely will save money by buying in bulk...
I would recommend these guys:
www.posterframedepot.com. They are local and will custom cut matts, I once called them with a standard size (multiple openings) and I want to say they quoted me under $2 a matt so long as I bought 50...
Hope this helps and happy collecting!