Yeah, splurging in Hong Kong certainly isn't cheap. $30 per night isn't going to do it
It's around 250 HKD - which is the right amount for a mid-range restaurant with soft drinks.
One place I like a lot is Lao Shang Hai in Wan Chai. Usually costs us about 300HKD each. I'm always a big Ding Tai Fung fan. But they have those in the US.
I don't know if anyone likes the street food (?), but personally I haven't found any that appeals to me.
HK certainly isn't a food lovers paradise like Korea, Thailand, Taiwan, Malaysia or Singapore (or even the Mainland!) IMO. Though I'm sure others will disagree.
That's not to say there isn't absolutely amazing food here! What I mean is what the locals usually eat.
A better choice than street food may be a cha chann teng. They have food that the vast majority of locals eat. You're looking at 30-60 dollars depending on what you have. Some have fairly decent food, but I don't know any well enough to give recommendations.
Have a look on a website called OpenRice. It's a big HK restaurant review site. You can search by type of food and area. But I think the price ranges they have tend to be too low. Plus, there's always the old trick of looking for somewhere that's really busy.