NameCheap domain registrar has been giving away ssl certs with new domains for a few years, tho' apparently they have to be used before April now.
There are advantages and disadvantages to having one, I don't want to be the one to p in your pool but you could lose revenue and be paying for the privilege. Do you use FireFox or Internet Explorer to browse? If you use FF then you don't notice but using IE you get a "Do you want to display nonsecure items?" option message (yes/no/more info) on an ssl webpage. Select no and you don't get any ads , there's just nothing there because they're the nonsecure content part. Most people that need proxies, those at work, school, libraries etc. use IE and don't have a choice, those, and the paranoid, will click no usually (I do) so there's no ads showing. No ads means no income and you need a unique IP address too usually, which cost $1 - $2 a month on top. It's a math thing, if you can make it up on proxified page ads it's not so bad, and it'll be less likely to be blocked, in theory, but it's a gamble imho.
I wouldn't want to stop you using ssl but you have to weigh up the consequences for and against, and keep an eye on those figures. If your income drops you'll know why and might want to take it off. I just thought you should be aware if you hadn't given it much thought already.
EDIT: It might be an idea to advertise as ssl but link as non ssl and have an 'enable secure mode' link to https as an option, like a padlock open and/or closed icon, that way the ads would still be shown by default. Or have the ssl switch on the browse page. It could be a selling point having ssl, I'm just too cheap to try it myself. I have more than 40 unused ssl certs from buying domains but don't have much use for them yet, I guess they'll be lost after April anyway.