The rarity system and its vague nature is the onliny thing I was dissatisfied with for 5e, and my players like crafting so . . .
I expanded the costs by rarity, then go through and find an approximate Caster Level needed to make the item, which helps determine costs.
[TABLE="width: 256"] [TR] [TD="class: xl65, width: 64"]CL [/TD] [TD="class: xl65, width: 64"]Cost (gp)[/TD] [TD="class: xl65, width: 64"]Rarity[/TD] [TD="class: xl65, width: 64"]Days to Craft[/TD] [/TR] [TR] [TD="class: xl65"]1[/TD] [TD="class: xl65"]100[/TD] [TD="class: xl65"]Common[/TD] [TD="class: xl65"]1[/TD] [/TR] [TR] [TD="class: xl65"]2[/TD] [TD="class: xl65"]200[/TD] [TD="class: xl65"]Common[/TD] [TD="class: xl65"]1[/TD] [/TR] [TR] [TD="class: xl65"]3[/TD] [TD="class: xl65"]500[/TD] [TD="class: xl65"]Common[/TD] [TD="class: xl65"]2[/TD] [/TR] [TR] [TD="class: xl65"]4[/TD] [TD="class: xl65"]1000[/TD] [TD="class: xl65"]Uncommon[/TD] [TD="class: xl65"]4[/TD] [/TR] [TR] [TD="class: xl65"]5[/TD] [TD="class: xl65"]2000[/TD] [TD="class: xl65"]Uncommon[/TD] [TD="class: xl65"]8[/TD] [/TR] [TR] [TD="class: xl65"]6[/TD] [TD="class: xl65"]3000[/TD] [TD="class: xl65"]Uncommon[/TD] [TD="class: xl65"]12[/TD] [/TR] [TR] [TD="class: xl65"]7[/TD] [TD="class: xl65"]4000[/TD] [TD="class: xl65"]Uncommon[/TD] [TD="class: xl65"]16[/TD] [/TR] [TR] [TD="class: xl65"]8[/TD] [TD="class: xl65"]5000[/TD] [TD="class: xl65"]Rare[/TD] [TD="class: xl65"]20[/TD] [/TR] [TR] [TD="class: xl65"]9[/TD] [TD="class: xl65"]10000[/TD] [TD="class: xl65"]Rare[/TD] [TD="class: xl65"]40[/TD] [/TR] [TR] [TD="class: xl65"]10[/TD] [TD="class: xl65"]15000[/TD] [TD="class: xl65"]Rare[/TD] [TD="class: xl65"]60[/TD] [/TR] [TR] [TD="class: xl65"]11[/TD] [TD="class: xl65"]20000[/TD] [TD="class: xl65"]Rare[/TD] [TD="class: xl65"]80[/TD] [/TR] [TR] [TD="class: xl65"]12[/TD] [TD="class: xl65"]25000[/TD] [TD="class: xl65"]Very Rare[/TD] [TD="class: xl65"]100[/TD] [/TR] [TR] [TD="class: xl65"]13[/TD] [TD="class: xl65"]35000[/TD] [TD="class: xl65"]Very Rare[/TD] [TD="class: xl65"]140[/TD] [/TR] [TR] [TD="class: xl65"]14[/TD] [TD="class: xl65"]50000[/TD] [TD="class: xl65"]Very Rare[/TD] [TD="class: xl65"]200[/TD] [/TR] [TR] [TD="class: xl65"]15[/TD] [TD="class: xl65"]75000[/TD] [TD="class: xl65"]Very Rare[/TD] [TD="class: xl65"]300[/TD] [/TR] [TR] [TD="class: xl65"]16[/TD] [TD="class: xl65"]100000[/TD] [TD="class: xl65"]Very Rare[/TD] [TD="class: xl65"]400[/TD] [/TR] [TR] [TD="class: xl65"]17[/TD] [TD="class: xl65"]125000[/TD] [TD="class: xl65"]Legendary[/TD] [TD="class: xl65"]500[/TD] [/TR] [TR] [TD="class: xl65"]18[/TD] [TD="class: xl65"]150000[/TD] [TD="class: xl65"]Legendary[/TD] [TD="class: xl65"]600[/TD] [/TR] [TR] [TD="class: xl65"]19[/TD] [TD="class: xl65"]200000[/TD] [TD="class: xl65"]Legendary[/TD] [TD="class: xl65"]800[/TD] [/TR] [TR] [TD="class: xl65"]20[/TD] [TD="class: xl65"]250000[/TD] [TD="class: xl65"]Legendary[/TD] [TD="class: xl65"]1000[/TD][/TR][/TABLE]
For example, here are the armors and their value and level needed to craft, at 250gp value/day (25gp/day makes high level items almost impossible to make unless the DM allows vast amounts of time to pass):
[TABLE="width: 629"][TR][TD]Property[/TD][TD]Example Item[/TD][TD]CL[/TD][TD]Cost (gp)[/TD][TD]Time to Craft (days)[/TD][/TR][TR][TD]Perception/Initiative[/TD][TD]Sentinel Shield[/TD][TD]7[/TD][TD]4,000[/TD][TD]16[/TD][/TR][TR][TD]Resistance (elemental)[/TD][TD]Armor of Resistance[/TD][TD]7[/TD][TD]4,000[/TD][TD]16[/TD][/TR][TR][TD]Swimming[/TD][TD]Mariner's Armor[/TD][TD]7[/TD][TD]4,000[/TD][TD]16[/TD][/TR][TR][TD]AC Bonus, Armor +1[/TD][TD]Armor +1[/TD][TD]8[/TD][TD]5,000[/TD][TD]20[/TD][/TR][TR][TD]Arrow Snaring[/TD][TD]Arrow-catching Shield[/TD][TD]8[/TD][TD]5,000[/TD][TD]20[/TD][/TR][TR][TD]no Stealth / Strength disavantage[/TD][TD]Mithral Armor[/TD][TD]8[/TD][TD]5,000[/TD][TD]20[/TD][/TR][TR][TD]Glamered[/TD][TD]Glamoured Studded Leather[/TD][TD]10[/TD][TD]15,000[/TD][TD]60[/TD][/TR][TR][TD]no proficiency req.[/TD][TD]Elven Chain[/TD][TD]10[/TD][TD]15,000[/TD][TD]60[/TD][/TR][TR][TD]AC bonus, Armor +2[/TD][TD]Armor, +2[/TD][TD]12[/TD][TD]25,000[/TD][TD]100[/TD][/TR][TR][TD]Animated[/TD][TD]Animated Shield[/TD][TD]12[/TD][TD]25,000[/TD][TD]100[/TD][/TR][TR][TD]Immovability / AC[/TD][TD]Dwarven Plate[/TD][TD]12[/TD][TD]25,000[/TD][TD]100[/TD][/TR][TR][TD]Resistance / related ability[/TD][TD]Dragon Scale Mail[/TD][TD]12[/TD][TD]25,000[/TD][TD]100[/TD][/TR][TR][TD]Fortification[/TD][TD]Adamantine Armor[/TD][TD]13[/TD][TD]35,000[/TD][TD]140[/TD][/TR][TR][TD]Etheralness[/TD][TD]Plate Armor of Etherealness[/TD][TD]15[/TD][TD]75,000[/TD][TD]300[/TD][/TR][TR][TD]Resistance (magic)[/TD][TD]Spellguard Shield[/TD][TD]15[/TD][TD]75,000[/TD][TD]300[/TD][/TR][TR][TD]AC bonus, Armor +3[/TD][TD]Armor, +3[/TD][TD]16[/TD][TD]100,000[/TD][TD]400[/TD][/TR][TR][TD]Immunity / AC[/TD][TD]Efreeti Chain[/TD][TD]18[/TD][TD]150,000[/TD][TD]600[/TD][/TR][TR][TD]Invulnerability[/TD][TD]Armor of Invulnerability[/TD][TD]18[/TD][TD]150,000[/TD][TD]600[/TD][/TR][/TABLE]