This miscellaneous :D postcard features Mickey Mouse painting. It is postmarked in 1989 and is white, I'm not sure why it is showing up as a light gray here.
The sender writes:
Hi, Thank you for the cute Walt Disney World postcards.
About the Disney dollars - it seems WDW print came in 1988. I will inquire around for you and let you know for certain.
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In case you were wondering:
Disney Dollars were first issued in May 1987 and originally came in $1 and $5 denominations. In 1990, Disney added a $10 bill.