Codecanyon

Of all the programs I have purchased from this bunch, only one has been truely good. The rest are hit and miss. Codecanyon does not give refunds - they keep them as credit and if it's less than $20 it can't be used to buy another program. Stay away from this lot - they hide behind their web site with no contact number at all.
Much of the crap they sell is out of date and will not run on the latest machines. After sales service would have to be the worst I have ever come across.
Just stay away and save your money for someone who supplies a time limited full program for tryout on your machine.

This website sells wordpress plugins and PHP scripts for your website. The support system is very flawed as you have to use a public comments section, so anyone can see your sensitive information. Some authors provide good plugins, but there are a lot of outdated crappy plugins too. You get 6 months of support but you can buy more for a fee. The good thing is you get lifetime update free. I recommend purchasing credible plugins that have lots of sales and good reviews, otherwise you won't be satisfied.