It does add up - - -
Especially if one takes into consideration the stuff that is already "on hand"" --
When figuring out the cost of an item, I use two sets of values --
1) Replacement cost of the materials used - considerably more than the cost several years ago!
2) What I actually paid for the materials used - most of the materials I have were purchased several years ago - even using those values, it can be quite an eye-opener!