To minimize support and allow different print colors, I made the parts separately. The flame is press-fit on the candle.  However, print the base with support, which adds just a few minutes.

Thread the LED wires through the candle.  Then add the diffuser and then the press-fit flame to the candle.   I used red filament for the flame. The diffuser is printed in Vase (Spiral - single strand) mode.  Then add the roof to the base.  It is press-fit.

The wires are insulated to near the end.   Remove some insulation to get better battery contact.  The (+) can be shortened to reduce excess length.   Sandpaper the end of each wire to provide more exposure to the battery.  I made a loop at the end of each wire so that the wire end goes between the loop and the battery.  The loop then presses down on the wire end onto the battery.  Check that all the wire that was sand-papered will turn on the LED.  Place (+) battery side in first.  Secure it with a disc that press-fits into the base.    More than one disc is provided in case your printer is a bit different from mine.

More light is diffused if you don't use the FLAME.

Store-bought parts (Amazon):

    CR2032 battery. (Note the PN indicates size, i.e., 20 mm diameter x 3.2 mm thick), 100 pieces for $19.  Sold by fuspowerus.

  LED.  They come flashing and steady in many colors.  Buy those with a built-in resistor for 3 volts, such as:  

         Battery:  CR2032.

         Steady white:  Micro Litz Wired Leads Whiktem 25 pieces for $9.

         or Pre-Wired Micro Blinking LEDs 0805 SMD LEDs, Sold by: ZHONGZHENG