We do co-op preschool. It is one, two hour session a week for 1-2.5ers, $40 a month. After 2.5, it ups to two, two hour sessions a week for $80 a month. You have to come to the weekly sessions up to 2.5 age, then you only have to come to one weekly session with your child. Some moms bring little babes in arms with them. Others find babysitting for that period of time. What about a babysitting swap with another mom in the same boat?
There are definitely preschools out there that offer reduced tuition. There are also preschools through the head start program for low income families. I would do a preschool search in your city on the internet and just call and ask them about cost. Or, ask around when you are at local parks.