A source tells the website, "They shopped for engagement rings They were really cute together. Paris was making comments about the rings and joking that her ring has to be at least 24 carats."
Hilton, who began dating Waits last summer (10), didn't walk out with an engagement ring on her finger but she did leave with a very special birthday present.
The source adds, "She walked out sporting a $25,000 white gold and black diamond encrusted ring."
The socialite has previously been engaged to model Jason Shaw and Greek shipping heir Paris Latsis.