Cheap hardware

I've lately noticed that Small Parts has discounted a lot of their inventory in Amazon's Industrial and Scientific store. As long as one gets free shipping with a $25 order or with Amazon Prime, the prices are lower than at my local hardware stores (and if one counts the gas, much lower). For instance, I needed two 1/4-20 knobs for a tailgate. Small Parts had a pack of five nice three-lobe female 1/4-20 knobs for about $1 (one can browse all their knobs by searching for "1/4-20" dimcogray). I needed three #6-32 collimation screws for a laser collimator. I got five really nice mil-spec stainless steel screws for a total of 30 cents (their mil-spec inventory seems really highly discounted)--my local hardware store has zinc plated #6-32s for about 12 cents each. Yesterday I needed two socket cap #6-40 screws for one of my Daisy RDFs, so I could adjust them by hand. A pack of fifty nylon socket cap screws was about fifty cents. (I am guessing that at Lowes they would have tried to sell them for about $0.75 for two, and I'd have to pay for gas.) I also bought two timing belts and timing belt pulleys for a $1.63--I'd have paid about $10 plus shipping at SDP-SI.
A lot of these items are marked as heavily discounted, by up to 90%, so I don't know how long this will last. They can't be making money on a lot of these. It's weird to shop online for items under 50 cents.
My currently going projects are: (a) digital setting circles for my 13" and (b) equatorial platform for the 13" (that's what the pulleys are for). I think I will also make a parallelogram mount for my binoculars.