D.G.
I would try to borrow one first. My oldest was born 11 weeks early and never really liked the swing and the specialist actually said to really limit the time in them - and not at all for quite sometime because of the positioning risks mentioned earlier. My baby now is 9 months born just 4 weeks early and she didn't like the swing until she hit full blown colic. The girls at work actually bought M. the Fisher Price take along swing (only $50) to try to give M. a break...and it helped sometimes. It's just a lot of money to invest if not going to be used or enjoyed!
...my sister and a friend swear by the moby. my baby just wants M.!