Microsoft Math - $20 - Wow
Microsoft Math 3.0 Wow. 3D graphing. For 20 freaking dollars.
When I was a teenager (Yeah, yeah, some of you are clicking on the next blog entry button.) I was teaching myself WatFiv and a bit of PL/C and S/360 Assembler at the local college after school hours. I was doing some graphing using some libraries of code which meant printing out the graphs using *+- and | on a 132 character dot matrix line printer. I was using punched cards and did a very little bit of work on a 24x80 text screen. No such thing as Windows or even DOS then.
Although the Altair came out soon thereafter. 8 Kb of RAM I vaguely recall. Or maybe it was 256 bytes of RAM. (Ah I'm right. According to Wiki It came with 256 bytes of RAM and you could order a 4 Kb RAM board for half the price of the initial computer.)
I was also doing some graphing with equations in high school where you had to put in the values of x and hand plot the values of y. Took minutes for each equation. I was thinking wouldn't it be so neat if we could plot the graphs on a computer screen, change a value in the equation and see instantly how the graph would change. The equations would become so much more intuitive rather than being just images in the text book or smudges of pencil on graph paper. Remember graph paper?
And now you get 3D graphing for $20. Wow!
(Note the reference to Microsoft at the bottom of the Altair Wiki page.)