Hello Rainday,
most 3D programs will offer you to calculate the volume of an object, and you can usually hollow out a part or construct a fill structure that will increase stability while still saving weight.
Of course with the resin it's best practice to leave a hole to drain out excess resin, but it's manageable.

With my "regular" FFF printer I can print a lot with 1kg, as I only print small things.
On the other hand, one bulky object may use up a lot of plastic;
What are you planing on printing?