Query: How big is Freespace?
I only have a 1G jumpdrive so...
ps. I'm running mods so I can't tell exactly how big FS2 is...
Just FS? you mean just the retail campaign? Too big. Barebones (just Retail FS2) runs about 1.2 Gigs. You might be able to squelch a low-res FS2 in... (eg, the HOTU version...) You'd want to use the FS Open engine, I believe, unless you had a no-cd hack for the Retail engine. Retail FS2 Launcher+engine (freespace2.exe & FS2.exe) = 3.38 MB, FSO 3.6.9 Launcher+engine (Launcher.exe, launcher6.ini, & fs2_open_3_6_9.exe) = 3.62 MB. Really, I'd use the FSO engine & launcher, just shut off all of the fancy options.
Actually, right now, if you wanted to, you could just get an external hard disk on
eBay. For example,
eBay item # 220082746484 (Brand new Seagate 300GB SATA hard disk, seller rating 100% of 186 votes positive) costs $70 US incl. basic shipping.
eBay item # 130078698502 (New USB 2.0 SATA 3.5" hard disk enclosure) costs $20 US incl. basic shipping.
So, for $90 US, incl. shipping, you've got a USB 2.0 300 GB External Hard Disk.

(I bought mine a while ago, it cost me $120 - $140 after shipping for 300 GB.)
All you've got to do is browse through & buy an internal hard disk - whatever type, PATA (old, narrow cable) or SATA (newer kind), then get an external drive enclosure - just be sure that it's either USB 2.0 or FireWire, whichever you prefer, and that it's 3.5 inch, unless you bough a 2.5 inch drive (laptop drive, FYI) - then you'd get a 2.5 inch, of course - and, lastly, make sure it supports the same hard disk interface that your drive is (PATA or SATA).
The good thing about 2.5 " drives is:
They are small
They are lightweight
They can be powered off of the USB cable (make sure you check the description of the enclosure that it supports this!)
-(thus, they are almost as portable as a flash drive)
The bad thing is:
They are more expensive (or less storage for the same price).
They are slower (4200 - 5400 RPM vs 7200 RPM)
Currently, a 2.5 " USB 2.0 SATA enclosure is about $25 US incl. shipping. (Item # 140084487967 )
A 2.5 inch, 100 GB PATA drive is around $80 incl. shipping. (Item # 140085540332 )
So, around $105...
Although, item # 150090772766 you can get the above 2.5 inch, already assembled together for $95 incl. shipping.
And, item # 150092359220 you can get 320 GB 3.5 inch, assembled, for $120 incl. shipping.
If you can, I would get one of the options above... they make life so much easier! (Yes, I still have my 1GB USB flash drive, it still works, but the thing gets full too easy - 'specially when you d'l from this place!

)
BTW, you can find in-between options, eg item # 120085024712 - New, 20 GB External USB 2.0 2.5 inch for $50 incl. shipping.
and item # 220081936402 - New, 40 GB External USB 2.0 3.5 inch for $42 incl. shipping.