steam
Spending more than $5 on Steam upgrades your account from a limited one to a premium one. I know there are a few benefits and privileges enjoyed by premium account holders, such as adding friends.
What other features do you gain access to as a paid member that limited members don't get?
If I recall correctly, early Tomb Raider titles used "Red Book" audio for music—that is, they played tracks straight off a music CD partition on the game disc and had no built-in music code at all. The game simply triggered the CD drive and trusted that the right disc was there and that the drive's audio-out cable was hooked up to the sound card.
(A common practice in those days was to swap out the disc after the game had started so that it would play a music CD of your choice instead of the music it came with—the game couldn't tell the difference.)
If TR1 on Steam is a straight port, then the ability to play non-CD music simply isn't a part of the game engine.
The "restrictions" you're saying you've got on your account do not match up with what Steam call a "limited account" - it is probably worth contacting Steam support to discuss the issues you're having with the Steam store.
There are four methods of earning Snow Globe cards:
Vote in the "Community's Choice" sale every 8 hours, for every three times you vote you get one card (that's one free card per day)
Buying games/software from Steam: for every $10 you spend on Steam you get a Snow Globe card
Trading with other players on the Steam market
Crafting other badges will result in a Snow Globe card for each badge crafted
One thing to note is that getting Snow Globes by voting for the "Community's Choice" sale requires that you be level 5 already.
Best Answer
According to Steam's help page:
So, I assume you are able to do the above after spending five dollars.