Honestly, a logitech SE service or SE them yourself it the best way to start. SE a keyboard which you can then sell for £100. (That's what I did to start off). Obviously do some research first to see what keyboards are more popular and will sell easier and for more. Then you'll have £100+ in which you can SE more products from other companies or just logitech and then when you have enough, you can start refunding (expensive items).
SE is the way though. Logitech is 100% if you have whats needed which for 30 euros is definite
Also you can do the logitech with any product but i find keyboards the easiest and it tends to take a month+ for your item to come. So making money isn't quick unless you have a job but that's probably the best way (unless you want to get into cracking accounts) which is just a job in itself as it's really hard to learn and time consuming gl though hope this helps