There are a number of allegedly 1/2" cheapie routers being advertised on eBay.  Do not be tempted unless you have easy access to 12mm routers as that is what the collet size is.

1/2" is 12.7mm in my book.

not always possible on the cheaper end routers, as items like collets are often model specific, and they will only sell replacements via the post, and usually of the same size as supplied with the router originally, when i had apprentices one of them had one bought for him as a gift, had really wierd sized collets, which did not fit any tooling available in this country.. parents got it at a "market stall"... managed to take it back in the end  luckily!!!
so in a way the warning is good advise!!
but i do see what you mean there D-D's .. on better quality if offered with just the one collet, you can buy spare sizes...