Are only an issue if you want to buy a couple of minis, especially commons. In that case, you're even smaller than a small fry and you've entered the "Convenience Store Zone" of pricing. But if you buy a decent number oif figures from a good seller (like Auggies or any number of others) the transaction cost is pretty reasonable.
The problem being detailed also said online retailer, who, likewise as local store may not, have a large enough selection of what you want so buying in bulk to save costs are viable when the bulk amount would be things you dont want, or they dont have enough of what you do want to be able to buy in bulk, so have to buy form multiple places.
When HeroScape got a bit big, people were selling repainted MageKnight for amounts that would make the new paint job actually lose money, but the prices were good for HeroScape players for minis and they were on average $1 max for any and some of the uniques/rares were even 25 cents, just so people could get rid of them repainted or not taking the los to reclaim space in their homes or storage.
When older DDM minis can achieve those prices across the board and the supply is high enough and demand low enough, then maybe online retailers will have enough for most people left looking to get them in bulk as was done for MageKnight, but the demand for D&D minis wont be that low ever, and with new minis coming out, the matching scale(this wa always questionable but i digress) will keep older ones at a premium on the secondary markets and the supply will remain low except for the minis nobody ever wanted anyway. Those that were in every booster for the set, and only barely useful for the skirmish game to begin with....
Also people still play the game itself in places, which means for the game, the minis are still bought on secondary markets which makes two competing consumer basis to get them as well which cuts the supply down to make the ones most people might need as mising from being able to get enough in bulk to make it worth it for some.
Thankfully I got lucky with some on eBay and have a good deal of things I like, but many minis are still not affordable at the secondary market collection piece prices.
Speaking of, anyone want a sealed set of Mage Knight Alpha Rebellion, or about 100 DDM goblin adepts?*
(*This is not an ad, but a joke to express the point of how a large supply doesnt provide the variety of enough things people would want.)