I'm going to add my two-cents worth and advocate tray processing.
Tray processing requires little expenditure and equipment and is easy to get started with. The downside is that it takes a bit of skill. I recommend sacrificing a couple of sheets and using them to practice agitation with. I also recommend using 5x7 trays for 4x5 film if you have them, and agitating by shuffling the film along the short axis. This is a lot easier to deal with than sheets in an 8x10 tray.
The danger, of course, is scratching the negatives. Try to keep the stack aligned and to pull the bottom sheet straight out (not up) and return it to the solution flat so that a corner can't dig into the negative below. You'll figure it out in no time.
Practice with the lights on till you are comfortable, then close your eyes and practice some more. When you feel confident, go take a few shots and try things for real. I agitate once through the stack every 30 seconds. Start with two or three sheets (one flip every 10 or 15 seconds respectively) till you get comfortable, then up the numbers in the batch. I can agitate up to 8 sheets at a time, but prefer to keep batches to 6 or less.
Do pre-soak when using tray processing. If you trip up, take your time; it's less damaging to slowly figure out what's going on instead of trying to keep the agitation scheme going. It's no big deal if you miss a couple of cycles.