how much is the shipping? you can buy one at naturalbabies.com for around $25 (that includes priority shipping)
as for size - ds is around 15lbs and fits fine in a small. that says it will last until about 20lbs. i think it might just make that - but then again i have an adorably chubby little guy! i like me alot so i have a large ready too!
DS is in a large at 22lbs (he's about 24lbs now) and it fits with room to grow, but is not or baggy. I am wondering if it will make it to 30lbs, but it could be because we only use it at night and his nighttime diapers are bulky.