It's important to look your best for your date in the Tokimeki Memorial series, though the shops aren't very clear of what kind of items they sell until enter and you can easily forget (which can be very tricky when you're limited to shop at 2 stores per your free day.
Here is a list of the shops and the items they sell.
Boutique JessLocated in the Shopping Mall
This store sells primarily Chic and Natural-type clothing
Boutique NenneLocated in the Shopping Mall
This store sells primarily Sexy and Vivid-type clothing