Both these services are widely used.

I don't know what "affordable" is for you, as it means different for different people.

P411 charges about $89.00 yearly. No lifetime option with P411. (preferred411.com)

With date-check, there are several options: $12.95 monthly, $24.95 quarterly, $39.95 semi-annual, $69.25 annual and $124.95 lifetime (date-check.com)

-- Modified on 12/8/2012 8:52:10 AM

As Curly said DC and P411 are pretty good and reputable.  I belong to both.  Also in the midwest is RoomService2000, or RS2K.  I know it's pretty popular in the Chicago area.  Don't know their prices.  DC and P411 have their servers outside the US, would not be surprised if RS2K does also.  They will charge your CC, but it won't have the site's name on the charge.

Swim

Not sure about the other services, but p411 accepts visa/MC, Western Union transfers, cash, or money orders. So there are options if you don't want to use a cc.

I bet you can also use a greendot cc or something like that also, if you don't want to use your personal cc (but I don't know this first hand)