I found the import square chisels and bits to be very affordable. They work OK, that's about all I can say. To use them you must open up the CM mortising attachment (or chisel holder as some refer that particular tool) to 3/4" I believe. But to get the collar size you need, you will probably have to locate a CM.
The quill on my CM DP measures 2 5/8". If you find a cheapo that is larger, they sell collars to go inside. This IMHO makes a poor tool even worse AFA lining things up.
Many will tell you to just go buy the dedicated mortising machine. That comes with most of what you need. The way I'm taking this all in is that a HF MM would likely be as good as anything you come up with and depending on what you have to pay for the individual parts. You can get the whole enchilada for around 200 with the coupon.
Edit: Well, I looked it up and I guess HF has taken them off the market as they are wont to do if an item doesn't sell well. I think I'll look for a used one just to have it.
