My sewing table is NOT portable, but a terrific, ultra-stable, large (30" x 72") surface that's terrific for all kinds of work.
It's an old cafeteria table that I pulled out of someone's trash pile at the curb. It weighs a bloody ton and was rusting along the lower edge and kind of grody on top. I sanded down the rust and painted the entire base. The grody top got a good scrubbing and a layer of clear press-on vinyl.
It ain't purdy, but I've been sewing on it for more than 15 years and wouldn't trade it for anything.
Moral of this story -- you don't need some $1500 (or more) "sewing furniture" to be a happy and successful quilter. You just need a stable surface that won't vibrate every time you put your foot on the pedal and that fits your space and your budget.