I buried this in an old post but just finished the second half of my sandwich for two great lunches for a total of $3.69. DJ's deserves it's own post. On Boston Ave about 3 block south of Dorchester Ave.
Oh my God! I just tried DJ's and it was very impressive. I had mentioned Euromart to a Polish friend who reminded me of this place. The Kielbasa sandwich was $3.69 and had a different variety of kielbasa kept warm in a little oven with some huge pork roast-looking thing in it. It was excellent and I could only finish half. Quite a statement from someone who downs a 1/2 lb Speed's hot dog and runs back to work. The place was lined up with burly men getting a hearty sandwich for lunch and one fellow picking up 30 lbs of kielbasa (presumably not just for his lunch). The variety here is less than Euromart but prices are about 30% lower. Thanks elizard and thekidd for the recommendation. My triumvirate of Polish places is now a fantastic four.