Hi Obliqua,
I think if it shoots without roots it is using the power in the bulb. At a minimum , if you have bought the soft bulb with wilted stem, I wouldn't let if flower if it recovers and would spray the leaves with seaweed. Then it may flower well next year.
Like Elaine above, I find it hard to pass on a bargain, and sometimes succumb. However experience tells me to pay a little more for top quality stock will be more rewarding.
I would give it a miss, on balance , and pay a couple of dollars more to buy great stock off recommended suppliers on this site.
Peter