Hi,
Got below info from one of the balloon BP that I participated recently, HTHs.
Shop you can go for Helium gas
BALLOONS R US
200 Turf Club Road,
Turf City, #01-39A
Singapore 287994
806 upper serangoon road
Call:62823916/96451069 Evan ($2.00 18")
Party with us
Centrepoint #05-01
176 Orchard Road
Singapore 238843
Tel : 62350221
Party with us
Valley Point #01-10
491 River Valley Road
Singapore 248371
Tel : 62350326
Party Joy
Parkway parade #02-k5 (opposite Mothercare $2.00 18")
Party city
252, North Bridge Road, #03-28, Raffles City Shopping Centre, Singapore 179103
Ph : 6336 2161
Shophouse 277A, Holland Ave, Level 2, Singapore 278994
Tel: 6462 6011
KK Hospital (Astoria florist $2.50 18" / Gift shop $1.50 18")
Thomson Medical Centre (gift shop)
SUNTEC (gift shop lvl 1 - ard $3.00 18")
CAUSEWAY POINT LVL 5 ($1.50 18")
TAMPINES MART LVL 1 ($2.50-$3.00 18")
UNITED SQ B1 ($1.50 18")
JUNCTION 8 (opp DBS $2.50 18")
Rocher Centre (opposite Sim Lim Square) have many such party shop, their price is the cheapest compare to the above shop