I ran an early MK2 8v as a daily for a good few years. MPG was usually between 35-40mpg and the running costs were negligible.
As mentioned buy totally on the condition of the body, rust/welding repairs are expensive unless you can DIY. I sold mine for a Mk4 1.8t as the only problem I had with the Mk2 was that it was beginning to feel old and I wanted something a little more softer/cosseting for my old bones, A/C, electrics, bigger, etc.
Having said that I'd certainly be tempted back into a mk2 8v again as I miss mine.