For some parts, JLCPCB doesn’t support Economic PCBA but charges 25$ per assembly side for Standard PCBA.
You can find out which parts are Standard only by checking the JLCPCB component list. Standard only parts are marked Standard only directly after the part number column while parts supporting economic PCBA are not marked at all.
Know parts include, according to my own research (this list is non-exhaustive and I don’t take any responsibility for correctness, beyond what’s legally required):
- Many ESP32 modules
- …but not all RF modules – e.g. this one is available in economic PCB
- Some ESP32 modules such as ESP32-SOLO-1C is available in economic mode)
- Some U-BLOX Bluetooth modules (but not all U-BLOX modules)
- Some ESP32 chips like this one
- WS2812 LEDs in 5050 package
- Round-top SMD LEDs such as this UV LED
- Some chip-scale package chips such as this EFM8 or this flash (but not all CSP chips)
- Some large BGA microcontrollers with 100s of pins such as this one