Short answer, it's complicated. Long answer, really, really complicated. Answer you actually need, talk to your DM or if this is for PFS just don't.
Now for how to break down custom magic items.
Step 1: Find flat modifiers. It's a masterwork bastard sword, no special materials, that's 335 gold. We're now at 50,000.
Step 2: Begin guessing wildly. The primary reason to do this is to figure out if the powers are flat cost or +X equivalent. This only matters for weapons and armor. We are currently at a price of 50,000. We have to account for the following powers:
- +2 weapon
- Bastard sword you can use as a short sword
- +2 enhancement v evil
- Double damage v NE plane or undead creatures and increased crit multiplier
- 1/day sunlight (sort of)
- Evil creatures take a negative level holding it
Step 2a: That's exactly the same as a +5 weapon, so we can treat it as a +5 equivalent weapon. This is the absolute most expensive scenario, and easiest to accept for a DM. Every other option is cheaper, so it's at most 22,000 to upgrade to +3 and 48,000 to upgrade to +4.
Step 2b: If it's not just a +X equivalent weapon we have to try to pull out the other powers and see if we get to another +X equivalent level.
Step 3: Attempt to break down the pricing for known elements. The 1/day sunlight effect is Daylight, but with a stronger effect and a different duration. 1/day command word daylight is 5,400, but that's for 50 minutes and it doesn't work like natural sunlight. The Sun Blade does work like natural sunlight but you have to keep swinging your sword over your head (which has no action listed, so presumably is free? Can't be standard because you need a standard action to do the command word to activate it). Maybe the bonus size thing is lead blades + impact? Continuous lead blades is 4,000, and impact is +2.
Step 4: Subtract the known elements and check again if you're at a +X equivalent weapon. We're not, no matter what we use from Step 3, so we move on.
Step 5: Eyeball the rest and guess wildly if they're meant to be +X equivalent costs. That +2 enhancement v evil is bane without the +2d6 damage. The negative level for evil creatures is straight out of holy. The increased size is impact. You can stop here for figuring out what it would cost to add +X equivalent abilities to it.
Step 6: Subtract your wild guesses on what the +X equivalent cost is to get the cost of the remaining powers. We're now deep into "make wild guesses and hope they're right". This is only useful if you want to apply the abilities of the item to a different item or combine it with another named item.
Final Step: Shrug, give up, call it a +5 equivalent weapon and point out to the DM that every other price would be cheaper.
