Jonluw said:
a single booster pack costs approximately 7.5 USD.)
Holy cow, what country are you in? In the US, the most you'll pay for a booster pack is about $4, unless it's A.)heavily in demand and B.)so old that almost all of the existing packs have already been opened. If you can find a decent card shop, you can often find older packs for $3 or less. Even if all you have access to is a walmart, they have packs that contain a booster and 30 random cards for all of $5. If you're just starting out, you can get a preconstructed deck for $10-$15, and then build your collection from there.
Basically, it can be expensive, but it doesn't have to be. I haven't spent more then 10$ on the game in the last few years, and the only reason I've spent that much is because the latest set is overpowered to the point that my old cards can't keep up. Regardless, $7.50 for a 15 card booster is highway robbery, and roughly twice MSRP.