dont finance toys, if you cant afford it just save up till you can
the only thing you should ever finance in your entire life is your home, and job related expenses like a work truck tools shop equip etc.
run the #'s if you finance the grom, if you make the minimum payment, you will prolly end up paying like $5-6k for your grom when its all said and done - and if you finance, the bank who owns the bike will make you have full coverage on the bike (to protect their investment)
if you cant pay for it outright - just save up until you can, ppl who tell you to finance a bike to build credit is retarded, you can build credit easily by making payments on your credit card, you dont need to open up extra debt to increase your credit score.