Advice. She should get a new boyfriend.
Just kidding. I was using the RE-0 for 3 months with Olive tips and wasn't happy with the bass. As soon as I tried the large bi-flanges, the bass grew exponentially.
You can get her a Shure E210/310, or a lower end Ety.
However my advice to you, is take your budget and double it. A year from now, you'll forget about the money and still have a killer headphone, no matter what you decide, My ex-wife didn't wan't me buying a new pair of rollerblades (she had a tight sphincter), so I bought a pair of $99 Lightnings (1992). I was doing 20 miles a week and wore out my abec 3 72a 78 mm wheels in 2 months and had to buy a pair of abec 5 $100 replacement wheels, The moral is, if I bought the TRS Lightnings for $199 which lasted forever ot would have cost me less in the long run. She was pissed at me for getting the $100 dollar Lightnings anyway. As soon as I left her, I got the the ones that I wanted and was in hog heaven.
It pays to get the better headphones and enjoy them, because it will pay of in the long run. Unless you are destitute, you will forget about the extra money quickly and really enjoy your sessions. Life is short and you shouldn't settle. In the end, it will pay off.
Trust me. Don't sell yourself short for short term gratification. It's your and her love. Eat macaroni and cheese for a week.