Sounds like you found a nice machine - maybe you can get it when they have a 50% sale - you should ask when the next sale is or if they will give it to you cheaper. Take a load of things that you don't want to donate - sometimes thrifts give out coupons for donors for discounts off of in store purchases. Hope you can manage to get it.
I wish our thrift stores here would realize what some of the current prices are for older machines. If they have an older one, they think that they have a pot of gold and ask for high $ - OBW they sit there forever until someone makes an offer or there is a sale. The Sally Ann here has a White treadle head for sale in their glass display cabinet - it is very rusty, few decals left and missing parts - price $95.