Making one ski does not cost a grand.
The raw materials cost approx $150 dollars per pair of skis, the problem is the material is usually bought in bulk.
Find a local machine shop to cut cores and such unless you have a bansaw and a planer (all that is really needed).
Actually pressing the ski can either be done with an expensive press, or can also be done by putting shit tons of weight on the ski like such:
Sandbags
Sandbags
Sandbags
Top mold
Ski materials
Bottom mold
Get creative, as long as you can find someone to sell you small amounts of base material, topsheet (not truly needed), etc... you could build a pair of skis for about $300 at the most. My dad buys in bulk and already has all the machine/tools so it comes out to $150 a pair.