If a store has last year's model, they may have them on sale now.

I have a Trek 1.5 which I still train and race on.  That's the same as the 2.1 but it had tiagra.  I upgraded everything a few years ago.

Maybe a bike with a lesser groupset, like the 1.5, until they really need to upgrade.

You'd need a huge tailwind to be in the 12 for any length of time.  I don't see you needing an 11 at all.

Aaron - I compared some common cassettes below. As you can see, most differences are on the ends. 

I would highly recommend getting an 11-23 for local racing though. You just never need anything larger than that for CP,PP,FBF, Branchbrook, local crits, etc. etc. 

sram PG 1050

12-28

SRAM PG 1070: 12,13,14,15,16,17,19,21,23,26

-or-

SRAM PG 1050: 11,12,13,14,15,17,19,21,23,26

SRAM XG 1090: 11,12,13,14,15,17,19,21,23,26

What's up with the 18?  Looks like it was included in the 7 and 9 speed cassettes, and continues strong for mountain bikes, but no longer for road bikes.  Now I'm suspicious it's that gear which will bring us (more) glory.

I will tell you what day it is.  It is approximately 27 months, to the day, that 'cross season begins.  If you haven't yet built up your pit bike (yep, in this bike racing-type sport you need 2 bikes per race, minimum) you are not only a shit but will probably fail.  However, don't fret.  I am here to help; you can thank me later.

I am selling a Shimano 105 (5600) groupset (crank, bottom bracket, front derailer, rear derailer, shifters).  I have had this group a while and don't need the race bike from which it came anymore (I have three others, don't worry, I'm covered).  As a result, I am repurposing the frame for another use.  The groupset is used.  It has had a lot of use and has the battle scars to prove it.  However, the entire thing functions perfectly and shifts better than the Dura Ace 7900 and Ultegra 6700 groups I have (we all know that Shimano put aesthetics over function by stuffing the gear cable under the bartape and the shifting wasn't as good.  Apparently the new Dura Ace 9000 and Ultegra 6800 groups have remedied this...).

A few deets:

Crankset: 172.5mm, 52/39t

BB: English

FD: clamp on, 31.8mm

Everything is the 5600 iteration except the BB which is the newer 5700.

I checked on Ebay and people are asking for $350-$450 for a used 105 groupset with these components (a bit steep I think).  I am hoping to get $250 for the lot.  Hit me up, you know it makes sense.  If you don't do 'cross, like me, bung this stuff on a $100 Nashbar "Alloy Road Frame", chuck those spare 1800g clinchers you have in your basement on and you get a 105 training bike for a total of $375 or something.  What deals!

Not only that, if you are a powermeter voyeur who goes around different websites looking at all the powermeters, lusting after them and then thinking how good it would feel to actually touch one, the crankset I am selling here can get a Stages non-drive side and off you go.  Just saying.

I have a load of BB30 to Shimano adaptors so if you have a BB30 frame already I'll chuck in an adaptor for free.

Also, if anyone is interested, a third 5600 105 shifter (left hand side, front derailer) for sale for $40.

I am also selling a 42 cm (c-to-c) handlebar, anatomic bend, 31.8 clamp, by Ritchey.  Again, used.  Asking $30.

I really like these bars but they are no longer needed.

Asking $20 for the pair.