Unfortunately, at the moment what you want is exactly what everyone else wants too. The Espace (whilst a bit creaky) was bloody good at doing its job cheaply and relatively reliably. The only word of advice I can offer is do not - whatever you do, and no matter how cheap it seems - consider a Mk1 Peugeot 806/Citroen Synergie/Fiat Ulysse. They are the biggest steaming turds of a car (well, actually a poorly disguised van) EVER
.
If you have one and its never let you down, well done you are one of the members of a very exclusive club.
I'd suggest you go for something deeply uncool as that'll keep the price down. Is a Mitsubishi Grandis or Mazda's deeply uninspiringly named "MPV" out of the budget