For the OCD Mom, you can take thrift hunting one step further. 

If you want to be really prepared you can create a ziplock or envelope for Thrift/Resale shopping.  I have created this a few years ago after having a second child and realizing the jumping in an out of the car to check out sales was not as quick and easy as it used to be when I was shopping solo.  In the ziplock (which I keep in the glove compartment) I keep my list and a pen, an envelope stocked with $20 in one dollar bills and $20 in 5’s, and a snack (something with a lot of peices that will preoccupy them for a while-  my latest favorite is candy necklaces).
 
Keep in mind that it doesn’t hurt to buy ahead for things that will cost you a lot to buy new and you are sure to need in the next few years. 

Examples of this for me are soccer shoes, ice skates, blue jeans, dress shoes(urghhh), life-preservers, rain boots and jackets.
 
Also, talk to your mom-friends about things that you are in need of.  A lot of times moms are out and about see an item that the wish they “knew someone who could use it” because it is such a good find.  Your needed item might be right at the tip of a friends fingers, saving you even more time and money.

Lisa