I guess I'll chime in here with my thoughts.
First, CheffoJeffo knows what he's talking about.
In a lot of ways, discounts equate to pricing shenanigans by the retailer. A retailer needs to make a certain amount on a sale, or they get hurt and when they get hurt enough, they don't exist anymore. Needless to say, they (smart ones) don't want this to happen, so any discounts that are offered are either due to a special deal from a manufacturer, or they know that they have normally high margins and a small discount won't hurt them. Large retailers often sell some items at a small loss to encourage traffic to the store in hopes of establishing new clientele, or in hopes that shoppers will purchase other items with their normally high margins, while they are there for the "deal". Some will even boost prices shortly before a big sale just to make it appear something costs less, when it really doesn't.
This is a different situation than the one for niche vendors who sell the parts you are looking for. There is a limited consumer base for these types of items. The vendors for these types of parts really only exist because this community exists, and the "home base" for this community is BYOAC. I realize this fact and therefore don't offer BYOAC members a discount, rather I attempt to price my goods at the very minimum I need to be able to keep the business, myself and the other member of the team afloat. If anything is left over, it gets dumped into new things which frankly, cost a fortune to have produced because of that "limited market" thing I mentioned earlier.
While our approach causes some difficulties for us in the way of not leaving room for a reseller to handle our products, we feel keeping prices as low as they can be and direct sales to be the best solution for our customers and the community as a whole. The bang for buck our products offer, demonstrates this. But we do sacrifice some profit when the orders are large enough to compensate for it. Commercial cabinet and panel builders who place large orders at regular intervals are given small discounts (which are frankly the most we can bear) because the volume of the sale(s) makes up for it.
But enough about that. You have a dilemma with a small budget, and you probably should look at swapping elbow grease for cash outlay. Ebay is a good source for used parts, that often times just need to be taken apart and cleaned to be fully functional again. If you don't mind soldering, and a bit of loss in performance/convenience, you can pick up inexpensive gamepad controllers to hack for your interfaces. There was a recent thread where this was discussed at length. We offer these as well, if you can't get them elsewhere.
Even if you got some kind of a discount through sellers here, you won't be able to make that $75 go very far. So it's probably going to require you to be resourceful to get what you want, and you'll probably have to settle for getting what you need.
Good Luck,
RandyT