Marketing online isn't cheap, so you need to stretch every dollar you can as far as you possibly can.
Tip - If you are building your own e-commerce site, while using an eBay or similar for funnel marketing, then add a discount code application to your site. This is a great way to really maximize your funnel marketing efforts, especially for drop-shippers.
You make the sale on eBay (or similar), your supplier sends the item to your customer. As a thank you for their purchase, you email them a promo code for a 5%, 10% or whatever, discount on their next purchase FROM YOUR OWN SITE ONLY!
This is one effective way to draw traffic through that funnel, which of course is what you are attempting to do.
Go one step further to really drive your marketing dollar. Create another discount for them. If they introduce a friend who purchases, the friend gets a discount as a thank you and they get another discount on their next purchase as well. Now what you are doing is creating a private commission based sales team to do your marketing for you through word of mouth marketing and you can be surprised at how fast and effective that form of marketing can be.
Building a strong reliable customer base doesn't happen over night, it takes time and it's all about coming up with ideas on how to stretch that dollar to maximum effectiveness and create a traffic flow through your store to start building that base as soon as possible that will then pay off for you long term.