Mini 64/128GB is 65/70k here. IMO 64GB variant is pointless today considering no expandable storage. I would say 128GB will just be enough for the next few years for most users.
For a cheap iPhone, 12 Mini is good as it has top of the line CPU, OLED display & cameras. The only place it lags over iPhone 12 is the battery life. So iPhone 12 is considered the iPhone for most people. Unless you need a very small phone, I'd say go for 12 over 12 mini. I feel 12 is compact enough, I'm also a compact phone user.
Compare Apple iPhone 12 mini vs. Apple iPhone 12 vs. Apple iPhone 12 Pro - GSMArena.com
My suggestion is based on the assumption that you are an Apple guy.
Yes, I'm still using an iPhone SE (2016) 32GB variant. I like the feel of compact phones, never owned a phone with a larger screen 5.5" or more. Also, lots of options available in the lineup to buy from the new iPhone SE, iPhone XR and the iPhone 12 mini. Don't think I can afford the price of an iPhone 12 but instead maybe choose the older iPhone 11 which has the very same battery life. I can keep the current SE for another year and wait for more phones to be released from Apple in the future, but the only reason I'm considering to purchase a new phone now is because there's a weird problem with my phone where when the device uses 3G signals to make phone calls or browse using mobile data, the battery of the device heats up abnormally and it shows a massive drain. Not sure, if the numbers reflect the true battery drain, it could also be a faulty battery but again when I tried different SIM cards the issue was still present. This phone was purchased in India, contacted Apple Support for if there is a hardware issue but after running a diagnosis test they said both hardware and the battery are fine. My battery health currently shows 84% capacity after 3 years of usage. The battery itself costs 50 pounds and the value of this phone at new condition is just 120 pounds and a used condition is 80 pounds.
I guess my budget to buy a new apple device is now 500 pounds, looking at mostly new condition phones and not refurbished. I can extend it to the price of an iPhone 12 mini but the iPhone 12 costs more than that. Btw, if you can tell what I can do with my iPhone SE please send me some suggestions. Overall, the phone just works fine except for this weird issue where I don't have a solution online. It happened since moving on to iOS 13 with the early updates after official release.