It's not illegal, but eBay has updated their TOS forbidding dropshipping from retailers (Amazon, Walmart, ....) they may suspend your account asking for supplier agreement to resell items on your store.
yes,you miss the train,the train tookoff long ago,and now the early birds are all making peanuts .
and risk being suspended by both Ebay and Amazon.
For something more than $5.I go to AMZN and avoid Ebay lest I ended up paying more to a dropshipper.