For Site-to-client sells, Magento or OpenCart(think that is the name) are good free solutions.
But when you start getting into scripts that allow User-to-User sells like ebay, or what etsy appears to be, you don't have much for options.
The only script that is free I found was: WeBid
It's pretty much garbage, but is free, and does work as far as I can tell. It would take a lot of work to get it to a production stage.
I installed it on a server I was working on, but never got around to working on that part. It threw a lot of constant cron errors and script errors.
With nobody using it.....
Now, I agree 1000 bucks is quite high, especially when code quality is in question. PhP gets messy fast.
I worked for a family friend once creating a auction site like this. I didn't write the script, just installed one.
PhPProBid. Compared to other scripts i've seen on the market, it is not bad. I think it was around $600. Ouch.
If you want to write, or contract a script that does this, and have it of competitive quality... your time and/or contractor investment
will be well over $1000.
There are just so many things that need to be covered on this script. Payment methods and interaction with their api's.
Shipping methods and interaction. Secure storage, organization, and display of data. List goes on...
There are free scripts that do part of the functions you'd need... but not to the degree your asking for. Its just too much code and there are not enough free scripts in this genre of site.