I had a similar situation. I had lost my first 20 pounds and was going to a convention away from home and would need nice clothes for almost a week. I realized almost all of my clothes were hanging off me. You can only do so much with a belt
Because I still have quite a bit to lose, I really didn't want to go shopping and spend a lot of money if within a month they would also be too big. So I checked out the local thrift stores. And boy was I pleasantly surprised!
So many of the items still had tags on them. The only bad thing was there was nowhere to try on the clothes and I wasn't exactly sure what size I would need. So after holding the clothes up and guessing, I bought 4 complete outfits...for a whopping $35.00. Only one item didn't fit. And when I 'outgrow' those, I will be donating them back.