I did a 3 months challenge of not buying soft drinks and saved almost $500 (and lost 2 KG), what other “money challenges” can I do to make saving more fun?

Wow!

Wow gratz. interested to know if $10 a day is possible (including bills, rent etc)

Can do many things
1. Bring home cook meals to work rather than buy. 3-5x a week
2. Use fan rather than air con. See your bill in 1 month
3. Spend less than $50 on dating/entertainment per week. You will realise there are alot of free things to do in singapore
4. There was a $5/day challenge.
5. Only home cook food allow, $30/week/pax.

Read more. Reading is the cheapest form of entertainment and enlightenment. Frame it as how it costs you nothing for the period of time you are consuming a book.

To motivate yourself further, post your book review on FB or IG to share your good reads with your friends and associates. I do this, and am always pleasantly surprised at how a particular book review resonates with a Friend.

Bonus: You will grow in confidence at your expanding encyclopedic knowledge!