Recommendations for a 'holiday' car seat please?

[Bouncearound]

Did is nearly three and tall and heavy. We use a Britax dual fix and Joie stages (both erf) but would like to buy an inexpensive lightweight car seat suitable for holidays and visiting family. I'm never 100% happy when we hire cars/ transfers with car seats and want to invest in our own.

Any recommendations gratefully received- ff is ok for the rare occasion!