1. They also sell big,soft pretzels.

Question

2. They also sell big soft pretzels.
3. They also sell soft,big pretzels.
4. they also sell soft big pretzels.

(Would you check the word order and commas? Which ones are grammatical?)

Answer 1

1 and 3 are correct, as long as you put a space after those commas.

They NEED the commas (so 2 and 4 are incorrect). This construction is called coordinate adjectives. See #5 here: http://grammar.ccc.commnet.edu/grammar/commas.htm