Buy TF2 item without buying Steam games first

Unfortunately, there's a restriction on the Steam Community Market to prevent fraud or scams from occurring. So yes, you'll have to make a purchase on your Steam account worth $5 USD (regardless of where you live) or more in order to use the Market. From their Community Market FAQ:

Your account must have a successful purchase older than 30 days, but not older than a year in order to access the Community Market. The purchase of wallet funds, games, DLCs and software meet this requirement. Retail CD key activations and gift purchases do not satisfy this requirement.

In regards to where you live and its effect on currency to this extent, this is elaborated on in the Limited User Accounts FAQ:

What if my Steam store currency isn't in USD?

If the Steam store isn't in USD, we will track the purchase amount in USD by converting each purchase total made on Steam using daily exchange rates. Once you have made the equivalent of $5.00 USD or more in total Steam purchases, you will gain access to the restricted Steam features.

Thus, if you don't want to buy something for the sake of accessing the Market, you could just put $5.00 USD worth of currency into your account's wallet (as this qualifies as a purchase for your account), wait for the purchase to be 30 days old, then use it in the Market, once you have access.