For my pastels, I have an arrangement with a local art store. They special order two sizes of wood frames which come with glass in three colors and discount them to almost wholesale for me. The 16" x 20" frames are $11, the 22" x 28" are $15. I buy mats and cut them at their store and use my mat cutter system (a cutter and a 3' board) to cut the double mats at my studio. I can resell them for $35 and $50.
The majority of my customers buy their own throughout the year, but at the peak season (which for me is November and December,) I do OK. The frames are very generic "studio frames", and are a convenience for many customers. I sell about 200 frames a year. I do not frame oils. I don't even have any oil commissions to frame!
Hoping that will change this year.