Marathon or Forward Facing car seat/booster

I have a 3 1/2yr, 33lbs, 38" in a marathon(2003). I have 8 1/2month old, 18lbs, 28" needing another carseat. Do I move baby to the marathon and buy toddler a car seat that turns into a booster seat or do I spend the money and buy another marathon? I posted a couple of weeks ago, took the information and went shopping. I was leaning towards buying another marathon when the man from the store (who was very informative) thought I should buy a car seat booster for half the cost since the age span for my children is about 3yrs. Infant moves to marathon and then to car seat/booster when toddler is done with it. Never going over the MFD of the carseats.

So if this is the way to go, which forward facing car seat that turns into a booster is best? I want safety, ease of use, comfort (for we travel some) and price.

Thank for reading this and for your help!!

I just replied to your other post! :) He's still pretty young and pretty small. If he sleeps in the car, or cannot sit absolutely in postition for every ride, not mess with the belts or lean over.... Around here, 4 is really the youngest recommended age for boostering, with most aiming much higher. We drive a lot and there's no way I want my DD in a booster at any time soon (she's nearly 4).

Your current MA will expire when the baby will very likely still fit in it. So, a new MA can be used now for the oldest, and then for the youngest when the current MA expires. This would also allow new seats to hit the market that might be great for the oldest. ;) MA's are on sale all over the place online, so worth a look!

Or, since your oldest is pretty light any of the combo boosters I mentioned in the other post are a great option if you are leary to buy another MA. Me? I'd go with the Recaro. Hopefully those last 7 lbs take a long time (well into age 4), then its a super nice booster with the added peace of mind with the side impact protection. Also good for sleeping and better staying in position. But, keep in mind that the youngest will need something too at the point when the original MA expires.