Filtering – use drop downs with set ranges, or text boxes for arbitrary values

If you are searching something, and want to filter the results, would you rather have text boxes to get exact ranges you want, or a drop down set ranges, that are quick and easy to select.

So the drop downs might have price, under $100, under $200, under $500, under $1000, etc, where as for the text boxes you could have prices between e.g. $33 and $76. More specific, but really people would only want a maximum price anyway most likely.

What is better?