Usually cheapest and best are not synonymous (sp?); if you want quality, you will have to pay for it. Trust me though - that few extra dollars you're spending for your reseller account will more than pay for itself once you have customers and you don't have to explain why the server is down (again) or their site won't come up (again). They will stick with you and tell their friends (at least, that's been our experience )
You won't neccesarily need the biggest account to start. Starting with a reseller package is a good first step. Remember that most websites are not larger than 100 MB and a lot do not take up more than 3-5 GB b/w. Most hosts are more than willing to grow with you and will make your transition from plan 1 to plan 2 very smooth.
Without knowing your budget, it's hard to point you in any particular direction. You can try placing a host quote (http://www.webhostingtalk.com/request.php) or checking the ad forums below. Just remember to do a little homework on your potential host first - search Google, search WHT.
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