Personally, I'd back, because I feel uncomfortable and naked without my packer. If you're uncomfortable not packing, then pack; and if it doesn't bother you either way, then you don't have to. You can pack with a sock clipped to your underwear (assuming you wear underwear XD), but you don't necessarily have to get a packer/stp.
If you want, the cheapest packer I know of is from Early 2 Bed (look under dildos). 12 bucks plus shipping. I'm not sure how fast they deliver (you could always pay extra for the quicker shipping) as I got mine from tool shed toys.
You could mod it as an STP if you want.