Hi,
It is great that you want to start saving seeds, but pear and peach seeds are not saved. Plants in the rose family need to be sown fresh straight into the ground or pot. If dried like most seeds need to be for storage, you will not get germination. Not many seed groups are like this, but these just happen to be like that. Citrus and many woodland plants also need to be sown fresh.
When people have wanted seeds that need to stay moist like from my Key Lime, I've harvested them out of the fruit as needed. I wrap them in a piece of damp paper towel and into a little baggie, and then mailed immediately.

Your box and old envelopes sounds like a good start for the other seeds you will collect. Seed saving can be addicting, but at least it is a cheap addiction! I have so many I actually have 5 different boxes. One for flower seeds from my garden, one for flower seeds I purchased, one for seed from other traders, one for tomato seeds, and one for veggies.
I keep each box in alphabetical order.
Keep your box in a cool, dry, dark place. I have my boxes in the coolest room in my house in a closet.
Remy

thanks for the help remy!! Thats that much more I now know.