One of the great frustrations of electrical engineering is part obsolescence, price and scarcity. In accordance with engineering law, half of what's ordered is never used and the other half's not enough. The most popular style of EE hacking that I've seen is a pack-rat approach where everyone amasses 'a few of everything', perferably for free or scavenged. Granted, IC's are relatively cheap for their functionality, ranging from $.60 for a 555 to $15 for a high-speed digital signal processor, but they add up fast. (Especially since you'll need at least 2 of everything in case you short one out.) Passives add a few dollars too, and connectors can end up biting you if they're not spec'd well. And all that after dropping a few hundred dollars on a scope, meter, power supply, function generator and EEPROM programmer, not to mention the wire, boards, hand tools, etc.
In these days of low-cost, all-in-one Taiwanese epoxy-boards, just finding someone who will sell you "3 of those" can be a headache. Many hobbyists, myself included, are leaning towards "if you cant get it from Digikey, then I'm not going to design with it." Regardless, there are some tricks that can make your small-scale project easier to manage...
- Samples: How to get free samples of parts from manufacturers
- Hobbyist: A list of surplus/hobbyist supply shops
- Distributors: A list of the large electronics distributors
- Direct: Some manufacturers will let you purchase direct, avoiding the middle-man distributor.