Will you be traveling through Hong Kong to Macau? Or directly? When I go to Macau, I always just book my same-night hotel at one of the agents at the ferry terminal in Hong Kong. Many hotels from $350 and up.

However, another problem is your travel date. That's just before the Canton Fair, and many hotels in the whole Guangzhou/HK/Macau region don't release inventory early on, or they sell at very high price.

No credit card is not a problem if you book at an agent in HK. When check-in, you just give them a HK$500 for deposit which you'll get back when you check out.