Ecommerce website development - advice needed

I am starting an eCommerce marketplace. I am about to give the go ahead to my designer to start work- however I have already paid 2000$ for development.
But, for the maintenance only he is charging me a 2,500 $( a yr) separately which includes - creating banners, backup of the website every 15 days,uploading photos/videos or logos given by us, bug fixing, providing traffic stats, and adding removing static pages, and security monitoring.

The problem is I am on a tight budget & considering the nature of the jobs - such as banners,uploading photos which I will want occasionally is it advisable to go with him or just hire some freelancers on elance and odesk ?

In short should I take maintenance from him or just hire freelancers to complete jobs whenever I need? what is better and cost effective ( 2500 for maintenance is too expensive for me )

Every situation is different, it's also dependent on the complexity of your e-commerce solution. That being said: backups/security is typically done by your web hosting company who I imagine you are paying monthly. "Hosting" is typically $5 - $150/mo. Stats are free if you are willing to go through them and figure them out yourself google.com/analytics.

So what you are paying/pre-paying for is help working on your site for banners, content updates and such. Not sure where you are at but freelancers are typically $50 - $150/hr here. So, if you are going to need 2+ hours of work a month and it's included then your yearly rate is fine.

If you don't think you are really going to need much help then you should just have your site hosted somewhere like: www.liquidweb.com www.godaddy.com ...
and consult someone here and there when you need something specific.

But - no, that is not an unreasonable amount or cost to have someone on call to help and helping you as needed each month.