Great parking is the lot by Boulder High School. Sometimes they ask for a donation for the school. But it's a quick walk to the market.
Chase has an underground parking lot that is free also.
I recommend parking in the parking garage off walnut. Its free on the weekends and ive always found a spot there. You'll have to walk a little to get to the market but with the new path by the creek its quite enjoyable on a nice day!
There are two parking lots designed for the farmers market. One ia jist past the market on Canyon and the other is just south of that, behind the food court. These almost always fill up early so its a good idea not to count on them. You can park on the street (pay attention to parking fees) or park a little ways away or simply take pubkic transportation which can drop you off at the corner of Broadway and Canyon.
Thanks! Your answer is awaiting moderation.