Is this an excessive cost for petrol? (Old Nissan)

[AntrimAerobics]

I go approx 100 miles per week and petrol costs me around £150 per month. I am wondering if this is normal or just because I have an old car. I'm saving up for a new car. If I get one, will I be paying less for petrol?? Thanks.

400 miles and £150?
Sounds like a lot to me.
I get more like 400 miles from £60-65, in a 1.6l petrol engine. My car tells me I'm doing 36mpg, so I guess your doing less than 20mpg. It is new. DH's new nissan does slightly better mpg with a bigger engine.
What type of car? ie is it very big?