For such a poor family, they live in a pretty big house, I lived in chicago a few years back, just recently, my old house came back for sale and was sold for $300,000. It was very small also, if i remember correctly, these are the sizes
Living: 17'x10'
Dining: 13'x9'
Kitchen: 11'x8' (incl. eating area)
MBR: 12'x9'
2BR: 11'x10'
3BR: 10'x9'
Family (in basement): 19'x14'
The rooms in Roseanne's house are huge.
Just an observation

i've noticed that too, but of course, but i think the set was made bigger so that the viewer could see everything. This is what i'm guessing the set looks like. The table kinda sucks and the chairs are too close to the couch but its kinda hard to do in paint.

judging by the stairs, the bedroom/bathroom are obviously on another set.

In All About Rosey part 2 she walks off set, you can see it's kinda like that, the set for Jackie's house was angled next to the living room and there was a big picture of the evansville house outside the front door. I imagine that they changed the picture to represent the neighborhood

yeah, i noticed that but I only wanted to draw the house

In the episode about tax paying Becky and Darlene say something about the amount of the house.

i think they said that they paid $30,000, which seems really low considering th size, but they always talk about how its in a bad neighborhood so that could contribute to the low price

I suppose that would lower the price, but still, I doubt it would be that low
Oh well. I wonder how much Jackie payed for her house

Well depending on when they bought the house. My parents have a pretty large house that they bought in the 70's for under $100,000 with a 30 year note. Just recently a house of their size on the same block went for $225,000. Houses 30 years ago were not half the cost they are today. Also take into account that if the house was built at a time in the area when there were fewer houses and the area was in development then someone could have bought up the land for cheap built homes and sold them under the price for an existing home.