My class has been collecting box tops all year. We won the first contest, and so right after that ended I told my students to keep collecting. The school usually has another contest in the spring, and I wanted a head start. The kids asked if that was cheating. I told them no, we were planning strategically. That's completely different.
The kids love to know how many we have, but I got sick of recounting each time. So I made this base ten/place value chart to keep track. Once there are ten box tops, they go into the small envelope on the bottom. Then once we have ten small envelops, they all get put into a baggie marked 100. Then, once we have ten of the 100 baggies, they will get put into the large 1,000 envelope.
I like it because it reenforces place value with something the kids care about. I also love it because when a student asks me how many we have, I can just ask them to look at the chart.
It's not pretty, but it works.