All of the above are great pieces of advice. I too have used various methods to sharpen my plane blades and chisels and I stick to no particular method(s). The situation will dictate what I need to do to get where I should be.
No matter what you choose, there will be an initial investment for equipment/materials. The question you have to ask, is this; what can I afford and what has the best payback? You don't have to get everything all at once. Build it up as you go.
I too, use garage sale finds, and with a little patience and a good eye can score you some really good pieces. I have gotten hard Arkansas stones for a little as 50 cents. New they would have cost upwards of $70-100.
I refurbish hand planes when I can find suitable users. I have found that the blades are generally in poor to trash conditions. As such, I have found that, if salvageable, my water stones and a lot of elbow grease is the order of the day, but initially, it may require a grinder or a belt sander. Once properly sharpened, a quick touch-up on a diamond, ceramic, or a hard Arkansas will be all that is needed to re-hone the iron for frustration free use. The same holds for my chisels! Once honed it only takes a few seconds on a hard Arkansas stone to reach that "really sharp" condition.
Some points to ponder.
Sandpaper is a fast and easy way to sharpen, but in the long run it will be costly!
I learned not to buy lower grit combination stones (220/1000). These will get the most wear (at least initially) and one side will wear out before the other. Single grit water stones are not that much more individually and will last much longer then combo stones. (my personal experience).
Learn what "sharp" really is. It may shave hair, but it may not be where it really should or can be.
When I started out I was proud as to how sharp I could get my various irons, that is until a more experienced person took my stones and in a few seconds, had them twice as sharp as I was getting them. Now I know and can recognize what "sharp" really is!
Bottom line, don't limit your options to just one method. Each has its pros and cons. For now, you can stick with the 'scary sharp' sandpaper method while you find or build up a collection of tools/materials to use for other methods. Again, all are viable and you have to decide what works the best for you.
Hi, sorry I missed you. I have gone to find myself, but if I return before I get back, please ask me to wait.
Nothing ever gets built on schedule or within budget.
Tool Storage Bait and Tackle, LLC.