Honestly, aside from accessibility issues, you'd be better off getting a faster connection if you can. The prices are really not as bad as you might think, and the lack of annoyance more than makes up for it. In short, I wouldn't limit myself to dial-up only, and explore my other options. You might be surprised at what you find.
Also, 3g is expensive. I doubt that it would be something you're interested in since you're looking for cost-effectiveness.