just built a rosin press (have a diary showign it)
you can very easily build a better one that is cheaper.
if you have a drill press, you can build one MUCH chceaper.
if not, you'll still save 100-200 and build a better device.
dabpress and other companies offer the platen kits. a 4x7 is ~300 and 3x5 is ~200... maybe you find lower, but that'll give a good ballpark idea.
3x5 - 12 ton press
4x7 - 20 ton press
if you wait for a sale at harbor freight (and in usa), you can get a 20T press for $150-170
you do not need the 'caged kits'. you can simply affix lower platen in proper position. i'v enot had one isssue with it shifting around. This saves a couple bucks too.
it is as simple as constructed the h-press... and simply putting the platens in position... tightening a few screws so the top platen is affixed to the press.
if you build the platens yourself, you have to use a drill press to ensure holes are level? straight? centered? proper terminology i do not have. it is near impossible without a drillpress though.
Seriously, build it... save 100-200 and get the proper max 2500psi to finish the job. (PSI calculated form surface you press, not size of platens. So a3x5 typically has a 2x4 filter bag. 8sq inch.. 10tons press would be perfect. a little extra is okay too.