In 1975, a "Pet Rock" cost $3.95. The pet rock is still available today and can be purchased from the Amazon website for $6 plus shipping. There is also a USB version available.
Not being familiar with a "toy rock" but remembering the "pet rock" craze of 1976, pet rocks then cost between $4 and $8. In 1977 the price went down to $2 before they stopped selling them. Seems you can buy them again for around $9 though.
$35
2340$
about $40
If you do it yourself, nothing.
$3500
1000to 3000
i bought my pet squirrels for 200 us dollars each.
from $40.00 to 55.00
1
900 dollars