You can find cheap tickets to most of this year's bowl games, but depending on the bowl, re-sell tickets are not necessarily available in huge numbers.
I scoured the TicketCity.com Bowl Section late Friday night/early Saturday morning and found that no tickets were available for either the Hawaii Bowl or the Bahamas Bowl. Both of those games are infinitely more difficult to travel to, and more expensive. Thus, the demand is limited, even on a first-sell basis. There were also no tickets listed for the Miami Beach Bowl or the Arizona Bowl.
At the other end of the spectrum, National Championship Tickets could be had for as little as $621. Only about 155 tickets were available for under $700. They were all in the upper deck, but I would suggest snapping up a pair immediately if you plan attend. If you're waiting to see if you're team makes it past the semifinals, you can always re-sell them yourself. At that point, the demand should be even greater.
Currently, tickets to the semifinal games are quite reasonable. You can attend the Cotton Bowl between Alabama and Michigan State for $26 if you're okay with standing room only. Or you can park your tushy in a seat for $125. Lower bowl end zone tickets will set you back around $250, on average, and great sideline seats are listed in the $500 range.
Clemson and Oklahoma fans can find Orange Bowl Tickets from $73 in the upper deck, and as low as around $200 on the sideline.
Here's a list of pricing for the other bowl games for which tickets were available:
Famous Idaho Potato Bowl - Utah State vs. Akron - from $8
Boca Raton Bowl - Temple vs. Toledo - from $12
Poinsettia Bowl - Boise State vs. Northern Illinois - from $36
St. Petersburg Bowl - UConn vs. Marshall - 6 from $154 to $273
Sun Bowl - Miami vs. Washington State - from $33
Zaxby's Heart Of Dallas Bowl - Washington vs. Southern Miss - from $42
Pinstripe Bowl - Duke vs. Indiana - from $22
Independence Bowl - Virginia Tech vs. Tulsa - from $11 on the Tulsa sideline. Only 3 tickets were left on the Virginia Tech sideline with 1 for $70 and 2 for $104.
Foster Farms Bowl - Nebraska vs. UCLA - from $20
Military Bowl - Navy vs. Pittsburgh - from $34
Quick Lane Bowl - Central Michigan vs. Minnesota - 20 from $97
Armed Forces Bowl - Cal vs. Air Force - from $25
Russell Athletic Bowl - North Carolina vs. Baylor - from $19
Texas Bowl - Texas Tech vs. LSU - from $35
Birmingham Bowl - Auburn vs. Memphis - from $36
Belk Bowl - N.C. State vs. Mississippi State - from $39
Music City Bowl - Louisville vs. Texas A&M - from $12
Holiday Bowl - Wisconsin vs. USC - from $66
Chick-fil-A Peach Bowl - Florida State vs. Houston - from $16
Cotton Bowl - Alabama vs. Michigan State - from $26
Orange Bowl - Clemson vs. Oklahoma - from $73
Outback Bowl - Northwestern vs. Tennessee - from $87
Fiesta Bowl - Ohio State vs. Notre Dame - from $75
Citrus Bowl - Michigan vs. Florida - from $76
Rose Bowl - Stanford vs. Iowa - from $199
Sugar Bowl - Oklahoma State vs. Ole Miss - from $102
TaxSlayer Bowl - Penn State vs. Georgia - from $50
Liberty Bowl - Kansas State vs. Arkansas - from $50
Alamo Bowl - Oregon vs. TCU - from $44
Cactus Bowl - Arizona State vs. West Virginia - from $26
CFP National Championship - Alabama/Michigan State winner vs. Clemson/Oklahoma winner - from $621.