Beginners really do have problems because they have no reference experience from which to judge a plane nor the skills or experience to do good restoration of old tools. Many of the tool restoration videos are good but they can vary in quality and not all planes require the same level of restoration detail. Scrub planes and jack planes simply don’t have to be finished to the same level as smooth planes. I recommend you find a woodworking club or mentor in your area who can take you into the shop and let you try out some properly set up tools and can offer you guidance. You can’t go by brand unless you are willing to pay for new premium tools. You will still need to be able to sharpen them and set them up properly to get them to perform well. I have about 200 planes and have restored all of them except for some of the newer ones. Nearly all planes can be fettled to work but some just aren’t worth the trouble or are best left to collectors. Keen Kutter, Winchester, and some of the other brands can be tolerable tools but will cost you more due to collector demand and really don’t work as well as most Stanley planes in my opinion. I have even fettled a Harbor Freight plane to do decent smoothing work (just for fun) but I wouldn’t recommend it. You really do get more “bang-for-the-buck” from Stanley planes in general and since there are so many of those on the market they tend to be more reasonable at the yard sales and flea markets. If you don’t want to spend your time on restoring tools then just buy new higher end tools but if you don’t mind learning the skills and spending the time to do the restorations you can save a lot of money and have some fun along the way. I am not a dealer but have sold a few items to fellow woodworkers who I have met that indicated a desire. I normally request that they come to the shop and spend some time with me learning about them, how to adjust and sharpen, and how to keep them working. They get to try out several examples of the type they want at the bench so they can pick out the one that suits them best. They get this for a lower price than what they would normally pay for a raw one on eBay. I really don’t make any money at it but have made some great friends and repeat “customers” They also normally leave the shop with an additional free tool (chisels, scraper, etc.), strop, or book related to their interests, just as my way of promoting interest in the activity.
I know that many woodworkers have trouble finding tools in their areas but do try to find your tools at the local flea markets, yard sales, and especially estate sales. You can do a first hand examination of any potential purchases and will probably get a better bargain compared to eBay. I would reserve eBay purchases for those items that you feel you must have but can’t locate locally. Have fun and remember that acquisition of quality tools takes time unless you have deep pockets..