I just opened a Gamersgate account to buy the X-Com bundle (the old games) and they are only "sort of" DRM-free. You pay for the games and then you download LINKS to the games (in this case, there are five games in the bundle, each of which requires installing separately). By double-clicking on these links (which appear as desktop icons) you then download and install the games proper, and this requires an internet connection. What this means is that if you want to uninstall and then reinstall a game you will have to be online and connected to Gamersgate. So if Gamersgate ever ceases to exist then (I assume) you will no longer be able to reinstall a game you have bought from them. So it's not DRM-free in the GOG sense of the concept. Please correct me if I'm wrong as I've only just joined.
And yes, you can buy games on Gamersgate which have some kind of DRM, including Steam. This information is always included in the product description (along with required system specs etc.) If you have a debit card you will probably need to open a PayPal account if you don't already have one, which is very easy. Again, please correct me if I'm wrong.