As of now, free players have no way to access the Personal Shop. It's reasonable to ask us to pay for the convenience of using it any time without restriction, but it's ridiculous to completely lock free players out of an important feature of the game. I don't care if you have to charge an exorbitant amount of SG for the tickets - I only need to buy one every few months so I can sell off cosmetics I don't want.
I suspect free players were excluded from the market to discourage RMT bots. This simply will not work. Bots only need to complete a few illicit transactions before being banned to make a profit. It's an expense, but not an obstacle. Instead, SEGA should focus on banning cheaters who buy Meseta and N-Meseta for real-life currency, and on automated ways of detecting and removing the annoying advertisement/spam bots.
Excluding players from the market only hurts player experience and stifles the in-game economy. I do not believe it will have any real impact on the amount of RMT happening.