if i get this hps, what else do i need?

so, looking around 1000bulbs seems to have the best prices on hps. i'm wanting a 250w for a small flowering room, mostly likely 2-plants at a time


if i buy this
250 Watt HPS HID Light Bulbs Light Bulb

then i need one of these
250 Watt High Pressure Sodium


but which one? i'm in the usa, in colorado

also, those ballasts, do they come with a cord with a fixture to put the light in? i figured i'd just hang the light straight down, and then hunt around for an alluminum shade to put on it, wrap it in mylar


so:
1. which ballast?
2. any suggestions for a cheap shade?
3. better suggestion on what to buy? any cheap full-kits? don't want more than 250w
4. where can i get mylar and black vinyl (for room walls)

also: could i consruct the entire grow room out of draped mylar? i was thinking of getting some poly and taping mylar on the inside, but as long as i don't rip it, the mylar should keep all the light in, and not let other light in? i can only seem to buy it in like 30' rolls which is more than i need, but since i'm using it anyway, why not screw the poly and just have mylar? i would just need to make sure no light gets through, but if it ever ripped, i'd just patch it with more mylar

they do not come with a socket or cord or ballast box you would have to purchase all those seperately and by then you would be better off just buying a complete light system with reflector might check out the below websites.
Complete Digital/Electronic Systems
Grow Lights » HPS Systems - InsideSun
mylar is very thin and really needs some form of backing to attach the mylar to.