This will basically unlock the game (45 minutes at a time, at least).
WORKS WITH TRIAL ONLY!
1. Move your profile to a preconfigured USB Drive.
NOTE: I'd suggest NOT running you trial completely out or else you may have to resort to removing the GPD [5841125a]
2. Start up CS:GO
3. Go ahead and play for most of the time.
4. Once your timer gets low (even upto 1 minute) pull out your USB drive.
5. At the error message, push A
6. When you're returned to the menu, you should see that the timer has reset.
7. Reinsert your USB drive.
8. Rinse and repeat as needed.

Research:
Didn't want to waste my limited time on my account, so I switched to a offline account. It was allowed to play so I automatically assumed that the data was in the GPD. Deleted the GPD and wallah, it was reset. I had hoped CSGO's demo would show up in the Achievements as some rare exception, but no it didn't (so long ideal noobproof method). I'm curious as to exactly what is stored in the GPD besides the time remaining.

Credits to bigtimer 5 @gametuts

Also sorry for re-posting but the CS:GO section isn't very active and this was and people who play CS:GO might use this more, also this topic does not need the arrogant people telling others 'everyone already knows this' 'this been out for ages' because I didn't know about this until today and I bet many people didn't know, and this is also a good method as you may not have money right now to get the MSP to buy CS:GO.

Please post legit once you have tried this out as it worked perfectly for me, you don't have to rep as its not my guide but welcome if you would like to.
Thanks, have fun.