Pardon me for being negative, but I have serious doubts about the viability of E-cigarettes as a stand alone business. If it works and they stop smoking after a week, where will your recurring sales come from? The chain stores include E-cigarettes in their product mix, so can be more aggressive on pricing. Will you be able to compete?

What will your R50k buy? An exclusive agency or just stock? What does the fine print say? Does that include advertising and promotion? Where will you sell from, online or from fixed premises? Or are you going to sell directly to the chain stores, in which case you'll have to pay a hefty listing fee and rebates etc etc.

Talking to family and friends is good, but can not be considered as market research as these are often people who who do not want to embarrass you by shooting you down.
R50k may not be enough to invest in a sustainable business. Are you looking for a short term opportunity or do you want to create wealth?