A screw costs how much???

So since we broke down and bought the hex wrench to put some furniture together I actually put the dining room table together (with much "help more work" from Andy and Jo).
Then we went to Jo's room to put together her crib. I had it 3/4ths put together when I discovered that one of the screws was missing. I was committed to getting the crib together because I had already taken down the pack'n play and she was going to have to have some place to sleep.
Since Jim was working on laundry I loaded up all the kids and headed to the home improvement store to buy "a screw." Of course I also thought...well if I am going to have to go there anyway I might as well also get a new blind for the boys' room (since they ripped off the old one that was only half stapled on) and I need to get something to take care of the previous owners installation of carpet on the stairs (where they had used staples and carpet tacks that were pulling up and Doug had already scratched his foot twice).
So... we found a screw that would work with some help from an employee.
Then I asked about the carpet issue and went to a different department to talk to another employee. This lead to a phone consultation with Jim to make a decision and get some measurements.
Then we went to get the new blind, but on the way remembered we needed more shelf liners. And, oh yeah, I passed the picture hanging hardware and we needed to get something to make a hanger for the picture of the kids the baby-sitter gave us for Christmas so I picked that up as we passed it.
So we found the pull down shade we needed but of course it needed to be caught so I have to wait for an employee to come cut the blind. Then I start thinking that if I have someone there already I should go ahead and replace the old shade in Jo's room and the master bedroom (since they are curling and cracked). So I have to call Jim again and get him to measure how long they have to be.
Then we go back and get the carpet transition piece since I now have measurements and all that from Jim.
Finally we get to go check out. Suddenly the one, less than a dollar, screw we came for has added up to some serious money. I don't know that Jim will let me go to the home improvement store again by myself....