I tend to buy a lot of Arduino and RasPi stuff (plus all the fiddly bits) off Amazon, so there are a few sellers on there that I trust to get good "maker" electronics.
Finally - if you're looking for low-cost but good quality DC gear motors - look into TSINY motors. They're a Chinese manufacturer. They have various vendors on Ebay and Amazon; some are almost (or seem like) "direct from the manufacturer", while others are "further down the chain". I can't vouch for any of them - only for the manufacturer itself (I wouldn't have any qualms with dealing direct with them for a large purchase - but I'm just a hobbyist, so that won't happen).
I tend to buy a lot of Arduino and RasPi stuff (plus all the fiddly bits) off Amazon, so there are a few sellers on there that I trust to get good "maker" electronics.
Finally - if you're looking for low-cost but good quality DC gear motors - look into TSINY motors. They're a Chinese manufacturer. They have various vendors on Ebay and Amazon; some are almost (or seem like) "direct from the manufacturer", while others are "further down the chain". I can't vouch for any of them - only for the manufacturer itself (I wouldn't have any qualms with dealing direct with them for a large purchase - but I'm just a hobbyist, so that won't happen).