I got in on trying ebay stuff as well. From the top of my head, the most pleasant price/performance I got were:
1, remote flash triggers (MK-RC7 i think), cost something like 15euro, work great as flash radio triggers, but also work as wireless shutter release : ) and then
2, a flash branded Godox TT520 for something like 26euros that I sometimes prefer to my (almost 10times as expensive) canon 430exii... it doesn't have some functions, but it can work as optical slave, it can be set as front and rear curtain, but mostly, in manual its so much quicker to change the power level... on a 430exii you need to hold the middle button for a moment, then go +/-, then push the middle one again, on the Godox, you just press + or - and you are done, so when I'm playing with some off camera setup, I find it more convenient. Oh and as a detail, the cheap one has a white reflection card, while the canon doesn't. And, I actually bought that from linkdelight.com, but they sell on ebay as well.
some other stuff that works great: quick draw shoulder strap with soft foam-ish shoulder padding, foldable 5in1 110cm reflector and stofen diffuser, simple extension tubes (intro into macro for a few bucks), some cleaning stuff
mixed feelings: gorillapod tripod (works great, but the screw rotates and can not be held easily from bottom, so I need to use a coin or something), battery grip (again, works great, fits well, but smelled badly when it came and it still does a bit some two weeks later), I also bought a ND8 filter that I wasn't expecting to be top quality, but I wanted to try it, get some experience and see if I have a use for it (or a different density) before I invest in an expensive one and it served like that (but has a strong red-ish color cast)
... but all for a fraction of the price of locally offered alternatives