Hybrids are always going to have a higher MRSP because of the extra tech in it.

For cars that might be in your price range while still boasting a decent MPG (can't say much about the engine because I don't know), the Honda CRZ has a pretty decent MPG (about the same as the Mazda 3) and AFAIK is reliable, but might still be small for your partner considering it seems about the same size as a Mazda 3.

Then there's always the Honda Civic 2015 - it's a spacious sedan, and it gets an average of 33MPG as well (30 city, 39 highway), and from what I heard is rather reliable. There's a reason why it's considered a classic in Canada. That's for automatic BTW - manual is rated at about 2 lower MPG.

And for larger, there's the Honda Fit which gets even better MPG (average 35, 41 on highway), at a similar MRSP. Haven't heard much of it though - but it may be a tiny bit too compact as I'm not sure of the dimensions.

Dodge has the Dart Aero to offer - which gets an average of 32 MPG (40 highway) with very little difference between the manual and automatic options - and it's a full-sized sedan. MRSP is still similar to the above models - but quick warning, the manufacturer instructs to use premium gasoline in this model.

Kia has the Forte - with an average of 30-31 MPG. May be a little too compact for your needs - but as far as I'm aware it's a reliable car at an affordable price.

A little bit more expensive (especially with options), there's the Mini family which has gotten roomier in the last few years. MRSP starts at 20k though, so maybe it's a bit steep.

On the OTHER side of the price curve, there's the Mitsubishi Mirage which is widely reported to have a MPG between 35-40 (and it's not a hybrid). I don't know about the reliability - but, while it's hard to tell from the pictures I've seen, the high MPG may be helped by a more compact size.

That's all I could find in the 20k-30k$ MRSP range with a MPG close or higher than 30. HOWEVER I'm no car expert, have no driving license and only have actually rode two of these cars (the Civic and the Forte) so only use this as a guide to start looking or getting more info. And this list is also most likely not comprehensive.

But hey, it's a start.