I agree. I remember that too, Auntie, about DS wanting his mother to sell the van. She didn't sell it, because she wanted him to have transportation so that he could work (you know, that 4-letter word:
W-O-R-K, that seems to be a stranger to him)?
Someone else pointed out, too, how DS ambled around all over Walmart, checking out various things -- like, when the McDonald's would be closing -- so he could have an excuse to leave the premises under the pretense of going to a McDonald's nearby with Cherish that was open at that time of night.
I do think he was under the influence of smoking crack, prior to getting to DG and Walmart, and he formed his grandiose plan to take all of them. But, as someone else very wisely pointed out, it would not be necessary to tie all of them up with the rope (as I had envisioned him doing). All he had to do was tie Rayne up and incapacitate her, and he could control the other three girls.
I think he probably had the means to pay for at least some of the items, or even everything, and I think that was his original plan -- rope and all. But, as his crack high wore off, and it got later, the night came on, and the kids were hungry and restless, he may have realized that his scheme was a little too "ambitious." It required too much energy and there were many chances for things to go wrong. He had to modify it -- make it more workable.
When the announcement was made that the store would soon close, he realized that he could just leave. But there was Cherish, shadowing him, and expecting him to buy cheeseburgers for all of them. He still could have told her to go back to her Mom and sisters, and left the store alone. When he made that conscious decision to walk out the door of Walmart, with her following behind, he knew he was already in trouble. He was a convicted sex offender, how would he explain it. It made him angry, but he did nothing to stop her.
Oh, well. It was her fault, he figured. He'd just have to kill her, that's all. He wouldn't have to buy any cheeseburgers, or anything from Walmart, and he wouldn't need that rope.