They're not terribly common, but they're not exactly rare either -- somewhere in between.
The prices on Alfas are usually all over the map. Most of the ones I see advertised through the Alfa Club are in the low five figure range, although I consider many of them to be over priced. I mean there's a difference between ten grand and fifteen, if you get my meaning.
Once in a while at the big fancy American auctions you'll see one sell for US$18,000 to US$20,000 (or more). All I can say is those buyers are suckers, or else they've got way too much money for their own good, and they should send some my way.
Of course, you have to take into account the dollar and the different markets between Canada and the U.S. -- the link I first posted is American. Usually a Canadian car would have a price tag of a few thousand dollars more (in absolute figures, although in relative figures, it usually works out to a bit less).
Now a high end mark-up shop like Bramhall usually has a couple of Alfas in the $15,000 to $30,000 range, but I don't put much stock in their prices.
http://www.bramclassauto.com/showveh...on=show&id=533
http://www.bramclassauto.com/showveh...on=show&id=429
http://www.bramclassauto.com/showveh...ion=show&id=14
http://www.bramclassauto.com/showveh...on=show&id=468
I might just phone on this one as there is no price listed and I need a good laugh.
Of course these two seem to be in about the right price range. I wonder what's wrong with them.
It must be pretty serious.
http://www.bramclassauto.com/showveh...on=show&id=380
http://www.bramclassauto.com/showveh...ion=show&id=33
Yes, I see the humour in the fact that the place that advertises itself as "your classic car specialists" and that offers a pricey appraisal service can't figure out that Alfa Romeo spells "spider" with an "i" and not a "y."
http://www.bramclassauto.com/photoads.php
On the low end of the scale, I just did a quick ebay.ca search and pulled these listings off. Now most auctions have a while to run yet, but even still, they seem a bit on the low side compared to what else has been posted there over the last couple of years.
Alfa Romeo : Spider MILES:49K 91 RED SPYDER VELOCE MANUAL CONVERTIBLE ROADSTER C $5,004.79 16 USA 16h 36m
Alfa Romeo : Spider SPIDER 2.0 1983 ALFA ROMEO SPIDER VELOCE 2.0 5SPD AIR FI NICE CAR C $2,625.97
C $4,757.64 18 USA 1d 04h 13m
Alfa Romeo : 164 Sedan Calif 164 Calif Black Beauty 164 Sedan C $2,640.80
8 USA 3d 23h 13m
Alfa Romeo 1966 Alfa Romeo Giulia 1300TI Solid Original RUNS C $1,668.26
USA 2h 38m
Alfa Romeo : Spider MILES:49K 91 RED SPYDER VELOCE MANUAL CONVERTIBLE ROADSTER C $5,004.79
16 USA 16h 36m
Alfa Romeo : Spider SPIDER 2.0 1983 ALFA ROMEO SPIDER VELOCE 2.0 5SPD AIR FI NICE CAR C $2,625.97
C $4,757.64
18 USA 1d 04h 13m
Alfa Romeo : Spider Duetto 69 Alfa Duetto 1750, California car C $15,076.15
C $26,568.63
7 USA 1d 15h 31m
Alfa Romeo : Spider ALFA SPIDER 1982 ALFA ROMEO SPIDER *ONE OWNER ONLY 27,000 MILES**** C $8,773.83
19 USA 1d 15h 31m
Alfa Romeo : Spider QUADRIFOGLIO 1987 ALFA ROMEO SPIDER QUADRIFOGLIO LOW MILES !!!!!!!!! C $3,770.27
10 USA 1d 19h 02m
Alfa Romeo : Spider 1983 Alfa Romeo Spider Veloce No Reserve C $519.02
11 USA 3d 00h 57m
Alfa Romeo : 164 L sedan Alfa Romeo C $1,528.38
2 USA 3d 01h 28m
Alfa Romeo : 164L 164L C $315.12
4 USA 3d 01h 39m
Alfa Romeo 164L C $123.58
1 USA 3d 10h 59m
Alfa Romeo Montreal C $18,412.68
24 USA 3d 16h 18m
Alfa Romeo : Spider Spider con. Alfa Romeo Spider graduate convertible FlA Car, BLACK C $1,361.80
9 USA 3d 17h 47m
Alfa Romeo : Spider CONVERTIBLE 86 SPIDER GOOD DRIVER ONLY NEEDS PAINT TO BE COMPLETED C $2,625.97
22 USA 3d 18h 48m
Alfa Romeo : 164 Sedan Calif 164 Calif Black Beauty 164 Sedan C $2,640.80
8 USA 3d 23h 13m
Alfa Romeo : Spider spider 77' ***** Romeo Spider Convertible Local Pick Up only C $370.73
C $617.88
USA 6d 19h 36m
Alfa Romeo : Spider Graduate Drive any where today! Needs "some TLC" Low Reserve C $1,946.31
Of course no Alfa for sale is ever a Canadian car.
They all come from the rust-free southern U.S. of A.
Yeah, sure.
--Toronto
It looks like the floor has dropped right out of the old Alfa market. Of course this is just ebay and not the real world, but still, I was hoping to see a few more cars in the low five digit range. 
