The problem going down the "cheap" route is that it always costs you more in the end, either through having to buy cheap and then the proper stuff later or in ruined work as it's not up to the task.

If you're going to get the ends machined, what you going to get them machined for? The cheap solution or the proper more expensive one?

Have you asked Chai (linearmotionbearings2008 on ebay) how much the ends are?

Even if you use a quick and dirty solution to tide you over you'll be surprised at how little difference there will be in total cost.