I have noticed a lot of folks looking for a way to find Infield RV passes for each weekends NASCAR race.
Each raceway handles the passes a little different, but a great way to get the REALLY GOOD ones is eBay.
I have seen the best spots at many tracks go quickly -  so check them out and bid like you intend to win, or you probably won’t (these things sometimes go for some pretty stiff cash).  While I can’t guarantee it -- they usually sell on eBay for less than the ticketbrokers charge.

Nascar tickets Las Vegas Kobalt tool 400 infield RV US $1,150.00 End Date: Tuesday Feb-07-2012 5:40:19 PST

Nascar Las Vegas Motor Speedway RV Infield Row 1 US $1,300.00 End Date: Tuesday Feb-07-2012 10:02:20 PST

NASCAR INFIELD RV FRONT ROW CAMPING LAS VEGAS KOBALT 400 $1600.00 US $1,600.00 End Date: Tuesday Feb-07-2012 17:09:12 PST

NASCAR KANSAS SPEEDWAY 1 RV INFIELD + 2 INFIELD TICS. SPEEDWAYCLUB APRIL 22 US $849.80 End Date: Wednesday Feb-08-2012 14:29:37 PST

Talladega NASCAR INFIELD RV Pass FRONTRUNNERS CLUB 2 US $2,999.99 End Date: Thursday Feb-09-2012 14:46:48 PST

Talladega NASCAR INFIELD RV Pass FRONTRUNNERS CLUB 2 US $1,699.99 End Date: Sunday Feb-12-2012 11:16:08 PST

Infield RV Pass for Phoenix PIR NASCAR Race - Subway 500 - ON THE FENCE! US $1,400.00 (0 Bid) End Date: Monday Feb-13-2012 21:06:47 PST

DAYTONA INTERNATIONAL SPEEDWAY INFIELD RV PREMIUM CAMPING SPOT ON THE "WALL" US $1,900.00 (0 Bid) End Date: Wednesday Feb-15-2012 11:41:12 PST

Nascar tickets Las Vegas Kobalt tool 400 infield RV US $1,150.00 End Date: Tuesday Feb-07-2012 5:40:19 PST

Nascar Las Vegas Motor Speedway RV Infield Row 1 US $1,300.00 End Date: Tuesday Feb-07-2012 10:02:20 PST

NASCAR INFIELD RV FRONT ROW CAMPING LAS VEGAS KOBALT 400 $1600.00 US $1,600.00 End Date: Tuesday Feb-07-2012 17:09:12 PST

NASCAR KANSAS SPEEDWAY 1 RV INFIELD + 2 INFIELD TICS. SPEEDWAYCLUB APRIL 22 US $849.80 End Date: Wednesday Feb-08-2012 14:29:37 PST

Talladega NASCAR INFIELD RV Pass FRONTRUNNERS CLUB 2 US $2,999.99 End Date: Thursday Feb-09-2012 14:46:48 PST

Talladega NASCAR INFIELD RV Pass FRONTRUNNERS CLUB 2 US $1,699.99 End Date: Sunday Feb-12-2012 11:16:08 PST

Infield RV Pass for Phoenix PIR NASCAR Race - Subway 500 - ON THE FENCE! US $1,400.00 (0 Bid) End Date: Monday Feb-13-2012 21:06:47 PST

DAYTONA INTERNATIONAL SPEEDWAY INFIELD RV PREMIUM CAMPING SPOT ON THE "WALL" US $1,900.00 (0 Bid) End Date: Wednesday Feb-15-2012 11:41:12 PST

NASCAR TEXAS MOTOR SPEEDWAY 1 INFIELD RESERVED RV-SITE APRIL 12-14, 2012 US $949.80 End Date: Thursday Feb-16-2012 15:45:53 PST

NASCAR TEXAS MOTOR SPEEDWAY 1 INFIELD FENCE ROW RV-SITE APRIL 12-14, 2012 US $1,449.80 End Date: Thursday Feb-16-2012 15:55:35 PST

RV Turn 2 Row 2 Nascar Daytona 500 Daytona FL 2/26/12 US $1,799.99 End Date: Tuesday Feb-21-2012 4:38:02 PST

Talladega NASCAR INFIELD RV Pass FRONTRUNNERS CLUB 1 US $1,850.00 End Date: Sunday Feb-26-2012 11:09:01 PST