I have only used the free Addoway option myself, but I know that the upgrade can offer you some great marketing tools including featured listings which can help boost your sales.
As a pro member, you can also create your own custom coupons for discounts or deals which you can offer buyers. I was speaking with the CEO and founder of Addoway recently, and he said that the coupons have been very effective.
You could try doing a monthly pro membership on Addoway, which is only $8.95, instead of signing up for a year at $75 if you prefer?
Even better, as a SaleHoo member, you are entitled to a 25% discount on a pro membership. Check out the details here on how to set this up: Link hidden: Login to view
Also, a couple of other things about Addoway:
Unlike eBay who spends gazillions of dollars per year getting buyer traffic to their site, and doing careful marketing to ensure it's the first place most shoppers go when they want to buy online, Addoway is more a platform for you to sell your items, and it's up to you to drive traffic to your storefront/ads.
This is why Addoway gives you a free blog, and encourages you to setup social media accounts such as a Facebook account that you can link your ads to, to help use the power of social media to drive sales.
We also have a user guide on Addoway which you might want to check out: Link hidden: Login to view (at the bottom of the page).
I hope this helps, good luck!