Bob Arum -- I'll Hook Ronda Rousey Up ... Free Tix to Pacquiao Fight!

Ronda Rousey can rest a little easier -- she won't have to pay MILLIONS for a ticket to the Pacquiao vs. Mayweather fight ... 'cause she's getting her tix for free ... TMZ Sports has learned!

The UFC badass told us earlier this week that she was concerned about the ticket prices for the fight of the century -- saying she had extra motivation to win the prize money at UFC 184 tonight so she could afford to go.

But when we raised the issue last night with Bob Arum -- Pacquiao's fight promoter -- he told us he's not only a HUGE Rousey fan ... but wants to HOOK HER UP with the most coveted tickets in sports.

#Respect