I bought a barely-used BabyTrend Snap N Go (Model #1305) at a consignment store for $25. It sells new for about $49-$59 which is cheaper than MacLaren's Easy Traveller. I think it's our best investment, even for a year (but I bought it used). It folds with one hand, and it works with any infant seat. I have the Graco SnugRide carseat and it works perfectly with it. Graco sells it's own version too (Graco Snugrider Carrier Stroller Frame ~$58).
It will be obsolete once your baby moves into a convertible carseat (or forward facing carseat). These systems only work for the infant seats. However, because its a lightweight frame, there's not much 'storage space' underneath the carriage. But the BabyTrend has 2 cupholders and a small storage space at the handlebar. It's designed to be folded with one-hand operation.
If you're worried about cost, look for a used one (since people only use it with an infant seat, i'm sure you can find one in fairly good condition)
I'm really happy with it. I've used it in the mall, airplane travel, walking around, and "quick" outings. Of course I opted not to get a travel system like yours. Just the carseat and this.
I read that BabyTrend was the first to come out with this type of "universal stroller frame". Now there's Graco's and MacLaren's version too..