Okay, 400 pesos for a preloved doppler with gel is actually a good deal, a few of us mums have passed ours around kaya mas sulit talaga! Just make sure it still works properly and na walang issue sa screen or buttons before bumili, lalo na if it's used na. Good on you for letting it go once you're confident na sa movements mo na, honestly that's the stage na you don't really need it anymore kaya smart move!