Brett,
You need to take a hard look at your need for making mortise & tendon joints. Only you can decide if it is worth the cost to you. I have had a dedicated Delta mortise machine for about 15 years. During that time I have used it maybe 5 or 6 times. There are other ways to make the joint without dedicated equipment. You got a good price for what you bought IF you use it enough to justify $40. But like you said, now you need a drill press just to use what you bought. That changes the bargain price a good bit.
You need to take a hard look at your need for making mortise & tendon joints. Only you can decide if it is worth the cost to you. I have had a dedicated Delta mortise machine for about 15 years. During that time I have used it maybe 5 or 6 times. There are other ways to make the joint without dedicated equipment. You got a good price for what you bought IF you use it enough to justify $40. But like you said, now you need a drill press just to use what you bought. That changes the bargain price a good bit.