shoes
Having reasonable footwear for tango can make all
the difference, particularly something that's
comfortable to move in and let's you pivot easily
on the ball of your foot. Sticky shoes (or bare feet
on the wrong floor) can make this hard to do,
and give your knees problems.
Although it's common for followers to wear heels,
and you certainly may, they are not necessary.
For practices like ours I recommend dance sneakers
or character shoes, as described below.
online

The Sansha Dynamo is a nice dance sneaker for tango,
about $40 at
nydancestore.com.
There are several similar models :
There's a similar sneaker at discountdance.com,
the
sansha "blitz-3" for $30 which I believe has the same sole.
The size of these shoes often don't match street shoe sizes.
Usually the site gives a fitting guide.
For Sansha, women order about 1 size larger
than street shoes, men order 3-4 sizes larger.
(Mine is a size 14; my regular shoes size is 10.)
If instead you'd like something with a heel,

Amber has found this
New York T-Strap
2" heel character shoe very comfortable,
for about $35 at discountdance.com
local
There's a dance store in Greenfield,
40 min south. They do mention "Sansha"
in their blurb; however, I don't know
what they do or don't have. If you
have access to a car (or a friend with one)
they're probably your best bet within
easy driving distance.
http://www.kdsdance.biz/dance_supplies.html
Karen's Dance Studio (KDS)
49 Bank Row, Greenfield, MA 01301
413-773-7816
dance@kdsdance.biz
Mon-Fri 12noon - 7pm
Sat 9am - 2pm