I just blew up my arduino (too embarrassed to say how).
I saw something called a Ruggeduino and it appears it's available for 54.95. I saw a post where someone said it was much cheaper than that, but I can't find a source anywhere except at the manufacturer's website.
I went ahead and bought one from the manufacturer, but would like to find this or a clone available somewhere at a discounted price.
I haven't seen a cheaper clone of the Ruggeduino. I wasn't that impressed looking at that board - it's a high price to pay for the durability which is only serving to protect you from doing things you shouldn't do anyway. I think it's ADCs will read bad values near the top of the range, too, due to the Zener diode. You've got to be mindful of the differences between the ruggeduino outputs and those of a normal Arduino board.
It does look like it could be nice if you're doing development in circumstances where accidents are frequent enough that the "buy the cheapest board and get some spares" school of thought won't work (have you seen how cheap Uno and Nano clones are on ebay? This is a higher bar than you'd think), or are using it in a hostile environment. But IMO, for most purposes, you shouldn't need the ruggedized arduino, because it protects against doing things that you should never do in the first place.
But no, I'm afraid I don't know of a cheaper source for them - I'm not sure if one exists, or how much room there is in the BOM for a cheaper version.
It's great you are supporting the company that invested so much money and design time.
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LarryD:
It's great you are supporting the company that invested so much money and design time..
Yes, I thought they deserved to sell at least one to me.
So for the price of one Ruggeduino, you can buy eight less rugged clones on eBay.
Hmmm.
Note that I have carefully avoided the trap of citing a bogus "UNO" which is actually a pseudo-Duemilanove. 
I like that they put their name over the image so people won't rip it off 
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LarryD:
I like that they put their name over the image so people won't rip it off
I don't care.
Actually, I am mildly promoting "Alice". I first bought some stuff from her some 2½ years ago and apart from the usual 3 week shipping delay, considered it good service and a reasonable price. I have found no fault with the components.
She appears to specialise in the electronic parts rather than bling and sex toys and also appears to know what they actually are, for example correctly describing USB to TTL adapters with the necessary DTR pin (though also stocking the less useful ones).
"GCsupermarket" and his aliases are pretty good too - I have fun in their auctions.
I think eBay - despite its nuisances such as obscuring pop-ups and permitting vendors to withdraw their items when their auction fails to reach the price they actually wanted with no way to complain about that practice - has realised that allowing hot-linking to their images through other sites is actually excellent advertising in itself.
PickyBiker:
I just blew up my arduino (too embarrassed to say how).
Do not worry, everybody has done the same thing at one time or another. 
Standard Arduino boards are just not designed for protection in any way, shape, or form. And the usual prototyping practice of inserting jumpers all over the darn place just begs for self-destruction.
One thing to do is to use an UNO board for prototypiing, and buy a few extra mega328 bootloader chips, and simply plug a new one in when you blow things up. And also stay away from boards using surface-mount processor chips until things are somewhat finalized.
The easiest way to protect the pins on a board is to put small value [220-330 ohm] resistors in series in the I/O lines. Then, short circuits and overvoltages will be less destructive. What you can do here is buy some plug-in prototyping boards and wire your own headers and series-Rs on it.
And always remember: "measure twice, cut once" and "look before you leap", or something to that effect. Double-check before applying power.
oric_dan:
And always remember: "measure twice, cut once" and "look before you leap", or something to that effect. Double-check before applying power.
...and before making ANY changes to a circuit, remove ALL sources of power.
And, upload an empty setup() and loop() sketch before connecting new hardware.
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"GCsupermarket" and his aliases are pretty good too - I have fun in their auctions.
I bought a few ATMEGA32U4 chips from them at a fraction of the cost sold elsewhere in retail and I was very pleased with both the packaging and the quality of the chips despite the low cost. I think they are the cheapest on ebay. (It did take about a month to arrive though!)