It is very difficult to compete on price and space especially with the big guys out there. The plans previously mentioned will cover most of the customers you will attract. Very few of my customers actually use the space/bandwidth they purchased.
As previously mentioned, you will have to look at your overall expenses, look at the overall profit you'd like to make and plan your prices accordingly. Don't use your competitors as your pricing model, but rather choose your prices based on your finances and be sure to make your prices in line with your competitors.
And first and foremost, you need to have a business plan. By creating a comprehensive business plan, you will have answered many of these questions.