Carrier: Boba 3G/4G
Library: All Three! We currently have 3Gs in all three libraries, and just got three 4Gs (two as donations from Boba, thank you Boba!) to replace or add to them.
Approximate Price: $125 for the 4G. 3G is discontinued but still available for around $100
My son had a very different opinion of the foot straps: no way, no how, not doing it and you can't make me. Once he got too long-legged to have good knee-to-knee support from the carrier (my kids are tall, so that was around 10 months) I sold my beloved Boba for a wider carrier.