There are a lot of the train stations on the way in from Stourbridge that have free parking, maybe Rowley Regis (although you'd be travelling to J2 of the M5 for that).
Woodgate Country park also has a free car park (though I'm not sure on opening times)
I think the McDonald's on the corner of hagleyroad/Wolverhampton road opposite the Triigate office block is unmonitored and restriction free. Might be worth checking out.