If I claimed $3250 as income from a 1099 and then discovered that it's actually $2485 is it worth amending or just leaving it slightly incorrect?

You should amend your return.  Of course, it is not required since you overstated your income by mistake, but it would probably be worthwhile to correct the error.  

If the income was reported on a Form 1099-MISC, not only will your income tax be reduced, but your self-employment tax will also be affected.  Also, changing your Federal Adjusted Gross Income (AGI) affects most state tax returns, so you should look at amending your state (if you file a state return).

Here is a TurboTax article to give you instructions for amending your return using TurboTax Online:  How do I amend my 2019 TurboTax Online return?

Also, some additional information:  Do I need to amend?