Mine will be the same way- didn't feel like spending 100+ on the bag and the cooler set. I ended up buying the cooler set at target and getting a 31 picnic thermal to carry the pump in. I totally said I was over 31 bags right before finding out that the medela didn't come with a bag, but it was what a coworker at work suggested after she realized the bag didn't come with the pump.
I've got my pump from last time (pre insurance buys you a pump) so I've got the medela bag. I like that it's sized for the pump and the little cooler bag, plus pockets and room for the other stuff. I like the pockets so I can keep stuff organized in the bag (extra tubes, flanges, bags, etc...) and I know right where it all is. I got a second pump this time (thanks insurance) so that I don't have to schlep anything except the milk (and occasionally the parts for sterilizing beyond the cleaning in the office).
Zulily has cooler bags for bottles at the moment for under $10/bag- some hold 2 bottles and I think there is one that holds four! I was lazy and shelled out the $100 for the Medela bag so I can't be of much help there.
I didn't want to drop $100 either. Target is having a diaper bag sale. I just bought one online. Looks like it will work fine for the pump and accessories.
I got the bag that came with the cooler and extra set of pump accessories through the company I ordered my pump through (SunMed) for $60. I wanted to upgrade to the on the go tote (for like $85) but at the time they couldn't tell me when it could be shipped to me because it was out of stock and I waited too long to order mine before my c/s, so I went with the accessories bag. I honestly wish I had a different bag for it that was a little larger, but I'm happy with the other items so ok okay with it.
Re: What do you schlep your breast pump in to the office with?
i don't even want to think about pumping at work...ugh.
but i would second the 31 bag/cooler route...i'm thinking when the time comes, amazon prime will be my friend too...ugh...too much to think about...