For the legal Winged Dragon of Ra when it is summoned can you pay any amount life points want to increase its attack and defense or do have all but 100 points?

You are correct! When you summon "Winged Dragon of Ra" by its own effect, you can pay any amount of Life Points you want, except for the last 100.

Here's the breakdown of the effect:

* Effect: "You can Tribute 3 monsters with different names. If you do, Special Summon this card from your hand. When this card is Special Summoned, pay any amount of Life Points, and this card gains ATK/DEF equal to the amount of Life Points you paid. You cannot pay Life Points for this effect, except for the last 100."

Important Points:

* Minimum Life Points: You must pay at least 100 Life Points to activate this effect.

* Maximum Life Points: There is no maximum limit on the Life Points you can pay, except for the last 100.

* Increasing ATK/DEF: The ATK and DEF of "Winged Dragon of Ra" will be equal to the amount of Life Points you paid.

Example:

If you have 2000 Life Points and pay 1900 for the effect, "Winged Dragon of Ra" will gain 1900 ATK and 1900 DEF. You will have 100 Life Points remaining.