Yep, figure about $25 a coin to grade. You have to consider how much more valuable the coin will be if/when it is graded. In this case, I'd say it isn't worth it.
On the other hand, if you 1888 is an O mint, and has a double die oberverse, or a scarface, you should have it graded as it will be worth quite a lot. AU double die is $3,000 and scarface is $1,000 ish.