I find that your prices are quite expensive. 10 grams of PLA cost 0,25BTC, or 81,79$ !!! 1 gram alone costs 8,18$ ! That's the price of Marijuana. When you'll sell plastic at the price of drug, you won't get a lot of clients...
It still have a lot to do regarding the price. If you order just 40 grams, which is nothing, you have better time to buy a whole 3D printer...
Also it may take a few days to print a fine quality large prints! (depends on the model size / infill % / layer-height ,etc..)
You think that you'r paying for the material itself ? just go and order the filament and one of those desktop printers on ebay ,and try it out .