How soon do you have to worry about smaller clothes?

Consignment stores are your best bet. You are going to change sizes a lot so then you won't be frustrated about not fitting into something you just bought if you only paid a little for it. Also if you have any sisters or friends who have gained or lost weight, see if they have any clothes they can part with and then dig deep in the back of the closet I bet you money you have a few things that you never got rid of that you will be able to get back into.

Thrift stores. I have a lot of very nice things, most of which were less than $10. Dresses and skirts are more forgiving for size fluctuation.

The only thing I spent a good sum on were bras. Seriously, as you lose weight, continue buying good, supportive bras that fit. You will look and feel better. Get professionally fitted. Keep the ladies hiked up. Your clothes will fit better, too.

Edited to add: I had to lose about 40 pounds before I dropped a size.

I definitely agree about getting good bras. It will make a world of difference because the girls are going to shrink.  

ThredUp.com is great for work clothes (my company is also biz casual) - good descriptions and you can buy quality for cheap.  I had a Talbots sweater and pants on for work the other day that I received complements on - I paid $30.  

A second vote for ThredUp. It has been a lifesaver and you can also mail them your old, gently used clothes for store credit - which I do with the clothes I've gotten too small for. Then I use that credit for my skinny clothes. :) I also buy a size smaller than I currently am, as I know I will fit into it eventually.

Personally I found properly fitting or even tight fitting clothing was an important part of my reducing phase.  It constantly reminded me where I was moving toward and most certainly boosted my self esteme.  I don't know about you, but when I was MO I spent alot of time in ill fitting clothes, I wanted to shed that skin a.s.a.p..

The good thing is you don't need to get full wardrobes, just a basic pair of pants, or other bottom & 2 tops.  You will burn through this in about 6 weeks, so not even time to get tired of it- or wear it out.

I am very pleased with myself that my size hasn't changed in over 2 years - this is a first in my fairly long life.  Also I still wear form fitting - tight clothes, why...because I can! Plus it keeps my body awarness in check.

Lots of terrific ideas here on picking up deals.

This! I held off on buying new clothes for as long as possible but once I started to dress for my smaller size, I found I couldn't go back to those sack-like body-hiding clothes. Wearing new outfits that I would have never been able to pull off before has been such a great boost to my self-esteem and really makes me feel attractive and fashionable. I have bought and donated a TON of clothes on this journey so far, but it's all been worth it for the confidence I have gained.

I had to within 2 months. But is totally depends on how quickly you lose the weight.  I've been about the same size for 2 1/2 months now, but clothes are getting loser. I'm looking forward to having to get the next size down.  I did have to get a new swimsuit.  And, the clothes I held on to years ago for when I would "get back down into them", are too large now.  That's a shame, because I kept them because they were pretty and nice, but now they're too big.  Not remorseful for that, though. 

I wouldn't go buy anything just yet - you may blow through a couple sizes to start. I would wear what you have for as long as possible.  I had my surgery about 6 weeks ago.  I was wearing 24 or 3x.  I finally had to buy a pair of dress slacks the other day - got a size 18.  I think its easier to get away with wearing larger tops.  I am down to 1 par of jeans - I'll hold a couple more weeks before I break down and buy a new pair.  I do need jeans / slacks to fit a little better.   Don't go shopping just yet - that's the fun part - to pick out smaller sizes!!  

I HAD TO GAVE NEW SHIRTS WITHIN 4 WEEKS. I HAD DROPPED 35POUNDS ON PRE OP AND WITHIN 4 WEEKS OF SURGERY I WAS DOWN PROBABLY ANOTHER 20 ISH POUNDS. ID GET A FEW SHIRTS FROM GOOD WILL ASAP