What can I buy with HK$135.70

You can buy one of the following:

Sweep Hand Puppet
Retro toys for £10 (HK$119.10) from hawkin
Coilhouse magazine
Futurist and alternative culture magazine for US$15 (HK$116.40) from source
Large Talking Bagpuss
Retro toys for £9.99 (HK$119) from hawkin
Manic Panic Amplified Long-Lasting Hair Dye
Cosmetics for US$15.99 (HK$124.10) from vampirefreaks
Duck Fishing
Toys for £10 (HK$119.10) from hawkin