Basically all the "hand pump" does is give one a place to put a handle on it to run the sucker rod, (for any pump over 20' deep).
one could easily make one if you jsut look at one and can or get some one to weld up one a a 2" or 1 1/4" nipple and then assemble it on a tee and another 3' short pipe. and some kind of well cap.
the trick is the double pivot points, on the handle so the rod can travel up and down in a straight line.
you will probly save some where in the $500. as most new pumps cost in the $600+ range.
there are two types, a shallow and then deep well pumps,
the shallow use a different type of pump many times, they use a "pitcher pump" (any way it has the pump in the top of the unit, one unit handle and pump), and it sucks the water up to it. 20 some feet is it maxim draw,
the deep well pump has a number of pieces, the top of it, the pipe type unit with a handle, Usually called the hand pump,
then it attaches to a pipe and in the pipe is the sucker rod,
and then the sucker rod and the pipe attach to the "Cylinder" which is the real pump, unit and some times under the cylinder is a screen and foot valve, some may say that it is optional.
nearly the same as in a windmill, but instead of wind you use hand power to pump up the water. (some times you will see hand pumps under windmill), so you have a choice on the power source.
if it is an existing well, and all ready has a pump in it, the biggest problem most will have is room in the well, some may also depend on what type of pitless adaptor the existing well may or many not have.
there are some very small cylinders, but the flow from them is very small as well, (you normally size the cylinder, pump) to the depth and power you have to move the pump.
so first you will need to determine if you have room in the well to accommodate another pipe, and cylinder, and if you do then a hand pump is a possibility,
( I think the 1 11/16" cylinder is the smallest available and takes a one inch pipe)
http://www.deanbennett.com/handpumps.htm
http://www.deanbennett.com/y2kwater.htm
http://www.deanbennett.com/y2ksimplepump.htm
if it is not very deep well the Tee handle may be the simpler way to go, and your cylinder is small diameter.
read the install links at the bison site, and you will get more of a feel for what one needs to do,
Cylinders
http://www.deanbennett.com/deepwellcylinders.htm
http://www.deanbennett.com/cylinder.htm
Ellen here has some good info as well on hand pumps.
http://www.windmills.net/handpumps.shtm
more point to windmills but still good info.
http://www.windmills.net/installation.shtm