Personal satisfaction is what you would have to put a price on IMO !! Generally I see finished arrows about $10 more a dz. at a shop. Then if you have them re-fletched it' s $2-$3 per arrow.
If you buy a quality fletching jig , arrow saw, epoxy,fletchings, fletching glue, etc. your going to have over $200 bucks tied up .......plus the cost of the bare shafts and/or components. Now just going with the basics .....that would be about 20 dozen arrows you would need to build to make up your investment. How long do you think it will take you to go through 20 dz arrows ?

Now on the flip side:

How often do you have arrows re-fletched ?
How convenient is it for you to go to the shop ?
How picky are you about having your fletchings done perfect and consistent?
How much do you like knowing how to do your own archery work?
Do you ever feel like switching to a smaller size vane or to feathers, etc. ?
Do you ever feel like trying more helical or less....or straight or offset ?

If all that kind of stuff is not important to you.....I' d buy them fletched !!

Personally I bought a used Bitz. jig w/ a helical clamp and a straight clamp from the local shop for $25 . He lets me cut my arrows on his saw....then I take them home and assemble them myself. My job looks much better than the factory applied fletchings that came on my first arrows......and I know they are more consistent than at a shop because my clamp is set up for my arrows and all of my arrows are done on one clamp ! It a lot of fun too !!