Don't know how they do it, the cp2102 is $1 alone, they use old version but that one have eeprom and not OTP, but there is not many settings you can change,
you can increase 5V enumeration from 100mA to 500mA (0xFA) in the settings, the onchip 3.3V ldo is 100mA.
I hot glued one to a P1, a little to much work to be worth it.
I also soldered the included 6pin right angle header downwards for breadboard, or get machined pins if you don't plan to leave it in permanently.
2.2nF series cap on DTR works just fine.
10pcs lot (mine showed up in 12days)
Some credit cards charge foreign transaction fee (like 3% so not much, but maybe yours have a minimum fee in dollars), I used a visa debitcard and no fee.
VCP driver for cp2102