Bicycle Mechanics - newbie question about bike gearing

I just purchased a sun usx, and would like to find the best ,hopefully inexpensive way to expand the gear range. It has a 7 speed cassette,14-28, and a shimano acera . In the front it has a 52, 42, 30 .Thanks in advance I love this bike, but i still love my hilly area.

I suspect that you have a spin-on freewheel rather than a cassette.

To get an easier hill climb gear, I'd replace your freewheel with a 14-34 freewheel. To make that work you will also have to replace your rear derailleur and get a longer chain. There's less expensive derailleurs, but I'd spend the extra money to get a Shimano Deore derailleur.

Total parts cost at LBS prices will be about $85.00. Labor to have the LBS do it would probably run about $25.00. You'll need a freewheel remover tool, a chain tool, a big crescent wrench and a 5mm allen key to do the job yourself. If you buy everything mailorder from someplace like Nashbar, you could probably save enough on the parts to pay for the bike specific tools plus you'd have no labor charge. That still may seem like a lot to spend to upgrade a low end bike, but it it makes the difference between struggling and really enjoying your bike I'd think it would be worth it.

Thanks for the suggestions. Could I also get a higher gear with maybe an 11-34 rear end, or is that only on a cassette? The high gear on that bike is pretty low. Thanks again

Thanks for the suggestions. Could I also get a higher gear with maybe an 11-34 rear end, or is that only on a cassette? The high gear on that bike is pretty low. Thanks again

Yup, 11-34 is available. Actual cogs are 11, 13, 15, 18, 21, 24, 34. The jump from 24 to 34 is pretty big, but I kind of like that feature. Whenever I have the need to shift into a bail out gear, I want to be able to really feel the difference.