Welcome to the forum. I will include below a link to instructions on how to submit, and it also includes the costs in the tier section. Economy, the cheapest route, will be $22 for coins under $300 in value. It goes up from there. Don’t forget shipping costs to and from the grader. You want to insure them so it’s not cheap to ship. Depending on how many you submit, how quick you want them back, etc you realistically are looking at all in costs of say $40-$60 per coin. Again it’s variable depending on many factors.
Before you submit if you will post clear, well focused pictures front and back of each coin you are considering many members here can give you opinions on if it’s worth it or not and a potential grade. General rule is unless a graded coin is worth say $200 or more it isn’t worth grading. Differing people set the threshold differently, and if the coin has sentimental value it’s irrelevant.
https://www.ngccoin.com/submit/how-to-submit/