used tri lock bits are for sale always.
we bought a used set. kept the press pallet, kept the expo unit jig, threw the rest away (sheets and sheet hangers).
inverted the expo jig on a board, built a raised center space to put the reg marks on, back lit it.
if you're doing FILM and have a press that fits a tri lock, this gets you (conservatively) 90% of the way to a CTS's accuracy with a minimal amount of extra steps (taping accurately mostly - besides being stuck with film).
costs: roughly $2k for the appropriate tri lock bits. another $100/$200 in building the FPU invert table/box.
in MY very biased opinion, anything LESS than that will barely be worth the improvement gains you'll see.
a WELL set up press, a good CTS and matching tri lock is HARD to beat.
but the well set up press is needed ANYWAY (so it's free). The tri lock is $2k used. The CTS is the part we couldn't justify the price point of versus what you can get with a bit of DIY ingenuity. (alan did it first, we all just copied him - his and mine and a couple others are fairly well documents on this forum).