well, here's my 2 cents worth...it would pay for itself...if you like doing it...and could be a (part-time) retirement way to make extra $$. if at all possible you should find a shop with a machine set up that offers classes..when i purchased my long arm i took a certification class on the machine, decided with practice it was doable and received a discount for the purchase. make sure if you buy the one you are looking at there is (tech support) somewhere within driving distance...you want a machine that you can get serviced when necessary...( i bought mine in Florida and live in Michigan...it sucks! i have no support and spend lots of time on the phone long-distance talking to reps in Utah when i have a problem) they are good, and have helped me, but sure would be a lot more convienient with something closer.
remember you are not going to set it up and immediatly quilt wonderful quilts...it takes practice......but with all that, it is a good investment, especially if you want to make a little extra, and you may find you make more quilts because you don't have to send them out.
i invite members of my quilting group to (rent time) on the machine, after they take a class($50) to learn to use the machine and do a couple practice quilts they can then call and set up time to come in and quilt their own for an hourly charge and i am here for help when needed and i help load them up and get it going...
good luck with your decision