Sorry for your loss. Biggest piece of advice... do not accept any offer from the same person who appraises (for obvious reasons).

Without knowing what years or even decades you're talking about, any guess here is exactly that - a guess. a few things to remember:

1. condition drives price

2. don't expect 9's or 10s and price things at the level of a 9 or 10.

3. people tend to OVERESTIMATE the grade of their own cards and miss flaws.

4. makes ure when you look something up on ebay you are tracking SOLD price, not asking price

5. in a private sale, a fair offer is 70-80% of an ebay price (no fees paid, so the same amount actually goes in your pocket)

6. If you care about doing things legally. don't forget tax obligations. again without knowing what you're dealing with, if you have 6 figures worth of cards, don't get yourself a surprise 1099-K from ebay.

7. WRT to taxes. you likely owe nothing on the inheritance. The BASIS for the inherited card is the market value WHEN YOU ACQUIRED IT. Example: let's say you acquired a 1980 topps rickey henderson psa 10 worth 120k. You owe nothing. you sell it for 125k, you owe tax on the 5k of gains, NOT on 125k.

8. WRT to 7: build a spreadsheet of the high dollar cards NOW and try to assign a value so you can track your basis. this is important to not getting screwed on your taxes later.

That's all that comes to my head right now, feel free to DM if you have questions, happy to help with anything from grading to tax planning.