Looking for foundation advice

I am about to build a 3' deep crawlspace alongside a full 8' basement.
The foundation for the crawlspace will hit perpendicular to the existing 8' high foundation wall. I realize that this puts pressure on the 8' high wall, and therefore I should step the footing down to the full 8' depth where it meets the wall. However, I'm looking for a way to do this in a more cost effective way. I could pour a sono tube next to the full height wall for the footing of the crawlspace to rest on. This may reduce the cost by then allowing me to pour the rest of the crawlspace's foundation wall at just 36" deep. Does anyone have any experience with this condition? Is there a simpler way of doing this? Perhaps providing a concrete pier on the inside of the full height foundation wall just opposite where the crawlspace's foundation wall will abut the full height wall? Thoughts? Thanks in advance!