Negotiating Time Saver for my closet

I've been finding myself in a difficult position lately when asked what's my "lowest" price. As a practice, I will politely refer you to the offer button. In my mind, that's the intent of that tool as it also protects the seller with a guaranteed sell. Like everyone else, I'd like to get as much return as possible and committing to a lower price in the posting then obligates you to stick with that amount. Also, my lowest may fluctuate. What I may accept today may not be the same tomorrow.