I often buy low priced stuff on ebay because I can sort by price including postage and that’s the price I pay and its bought in a couple of clicks
Except the OP is talking about an auction, you have to wait for the auction to end, so it’s certainly not quicker.
How long would you be willing search for to save the 62p in the OP?
The fact that someone is buying a good quality component would suggest they know something about cycling and the knowledge to fit themselves.
Personally I don’t know any regular cyclist who doesn’t know about Chain Reaction, Wiggle, Ribble and Merlin. It takes just a few seconds to check those sites and find that the 105 mech can be had new for <£30 delivered.