help me choose a budget bag

Well, I was gonna say Campmor brand bags, but I don't see them on their site any longer.

Check out Steep and Cheap gear cache right now. The camp category. There are a lot of good women's specific sleeping bags on sale right now for under 150.

these are a little over 100, but nice ones: http://www.steepandcheap.com/gear-cache/camp/BAG3006-MAR

http://www.steepandcheap.com/gear-cache/camp/MHW2383-SPR

And 160 for a down bag:
http://www.steepandcheap.com/gear-cache/camp/MHW005V-FREBL

Under 100 from my local Seattle store:
http://secondascent.com/hiking-and-backpacking/sleeping-bags-and-pads/marmot-womens-trestles-30.html

Kelty Cosmic Down 20 can be found for around a 100 or a little more, and is a pretty decent bag for a great price. Used one myself for a couple of years.

Try searching eBay for "down sleeping bag". There are plenty in your price range, you just have to know what's good quality and be willing to buy used.

The Kelty Cosmic Down 20 has plenty of positive reviews on BPL. Also you could always post a WTB ad on Gear Swap and see if you get any decent offers.

+1 on the Kelty cosmic down. I picked one up new for $89 on sale at sportsman warehouse last year for the kids. 2.5lbs if memory serves.

Keep an eye on Geartrade.com. Backcountry will sell lightly used sleeping bags there which were returned by customers. My ULSS#3 looked like it was unused and was discounted > $100 off of retail.

Keep an eye out for Somnus sleeping bags from Backcountry. I've never seen one but have heard they are good quality for a budget bag.

Good luck

The Kelty Cosmic 20 is probably your only realistic choice, assuming you don't find a deal somewhere. One of my usual hiking partners has one and likes it.