A cheaper alternative is park your car at Mid Valley and take the lrt from Abdullah Hukum station to Bangsar.
Total cost should be less than RM30 for 12 hours parking.

Parking Rate
On weekdays
The first three hours – RM2
Third and fourth hours – RM1
Subsequent hours – RM2.50

On weekends and public holidays
First three hours – RM3
Subsequent hours – RM1