You'll really be doing yourself and your skis a disservice using the cheaper adjustable tools for sharpening edges. I have yet to find one that can really hold a consistent edge angle (and I own a pile of them) - they vary way too much depending on how you hold and pressure the tool. And if you don't have a true bench with a ski vise then forget about getting any kind of accuracy.
What I suggest is that you "run the numbers" on how often you ski, how often you get your skis tuned at a shop, the total cost for a season, time to get the skis to/from the shop, etc. Then see if those numbers can justify tuning yourself. Take the dollar amount for what you would spend on tuning for the season "outsourced" and then start looking at "real" ski tuning tools.
Good edge bevel guides, etc. will cost upwards of $75 or more. Then add in files, etc. BTW - there is lots of good advice and info on specific tools in the ski tuning forum.