When to sell all of your old stuff to make the most money

An easy way to make some extra money is to sell your unused stuff. However, if you don't know when to sell certain items, you can lose out on some major cash — up to hundreds of dollars, in fact.

Luckily, INSIDER spoke to OfferUp — a popular online and mobile marketplace that rivals Craigslist— to find out what you should sell each month to make the most money possible. Check it out below, and start earning more for your stuff.

All data provided by OfferUp represents average item purchase price.

First up, January's the best month to sell your TV.

If you bought or received a new TV during the holiday season and want to sell your old one, don't wait too long. OfferUp users who sell their TV within the first month of the year earn an average of $189, compared to just $170 in June.

Sell engagement rings and other jewelry in February, just in time for Valentine's Day.

You'll earn an average of $870 if you sell an engagement ring on OfferUp in February — pretty impressive considering you'd only earn $690 if you were to sell the ring in October.

If you're itching to sell your old convertible or sports car, wait until March.

According to the DMV, convertibles and sports cars sell best in spring and summer. On OfferUp, people who sell their cars in March see less competition with other listings. They also earn $243 more on average compared to people who sell their cars in February.