That's why we can create some cool things that are also efficient with little resources. Big companies will dump a lot of money to realize the same results.
Since a lot of us are doing software and web stuff, there isn't a lot of cost-related items we shouldn't skimp out on. We can even skimp on hardware in the early stages (just make sure to have the appropriate servers for launch).
What we really should not skimp out on is fundamental decisions in design -- in our code and in our "backbone" implementation. These things are addressable later too, but it could cause headaches. The next thing is relationships and talent. Don't compromise on your founding team in regards to talent or passion. Don't insist on making it work when it's for the wrong reasons. A team needs cohesion.