Weed whackers.  They are cheap, work ok for practice and much lower stress on the instrument.  You can buy Weed whacker strings from online rockabilly suppliers or your can literally just go to the hardware store and buy string trimmer line.  $20 will get you a lifetime supply of strings.  Check out this guy its where I got the info for mine.

http://www.dennishavlena.com/db.htm

Quoted from above website.

"Some words about strings (whew!!) Being extremely adverse to 
spending upwards of a hundred bucks for commercially made strings, 
I spent far more time diddling with strings than I did building 
the instrument itself. I lucked out & discovered .080", .095" 
& .105" monofilament weed-whip line for sale at the local Tru-Value
hardware store! This stuff is Tru-Value brand name so it should be 
available widely. It proved to be excellent for the highest pitched 
three strings of the instrument (G, D and A).

The thickest string (E) was another matter -- I could write 
many pages about my numerous experiments to make a 
good-sounding/playing E string -- Some of the experiments I tried 
included...
- 24 strands of twisted artificial sinew (not loud enough) 
- Strands of twisted plastic covered small-gauge multi-colored
  telephone wire (nice loud sound, but rough on fingers)
- 1/4" cotton rope (!) didn't sound too bad but again irritated 
  fingers
- Various lengths & thicknesses of hardware store nylon/poly rope
- 6-conductor, gray vinyl-covered telephone interconnecting cable
  which actually sounded pretty good!
- I epoxied 50 lengths of stretched, 15 lb monofilament fishline
  into a nice looking round "cable" -- sounded "thuddy"! 
- Tried silicone gluing together the same number of 15 lb fishlines
  & it sounded nice, but the silicone didn't stick good to the
  fishline & made a flaky mess  
- Etc etc

I settled on "5/32 inch vinyl coated clothesline wire" (product 
#955) bought at K-Mart (saw the same stuff recently sold at 
Wal-Mart too). It has eight.012" hardened steel wires coated with 
smooth green, see-through vinyl. The sound and playability is much 
better than the next "runner up" & I am almost satisfied that I've 
found the elusive E string - almost! Oddly, there is no brand-name 
on the package other than the invitation to contact their website 
at http://www. lehighgroup.com. Experiments on this front continue."

You are correct about bowing and tension.  I forget that bows aren't just for fiddles.  I even put a flat bridge and fingerboard on the bass I built.