The Telemarketer

Up to you ;)

Expanded Spell List

The Telemarketer lets you choose from an expanded list of spells when you learn a warlock spell. The following spells are added to the warlock spell list for you.

Fiend Expanded Spells

Spell Level	Spells
1st	create or destroy water, command
2nd	enlarge/reduce, levitate
3rd	haste, lightning bolt
4th	phantasmal killer, fabricate
5th	seeming, greater restoration

But Wait, There's More

Starting at 1st level. When expending your last spell slot you gain a token to cast a leveled spell at a level equal to or lower of half your proficiency modifier (rounded up).

This token has an expiry date and is inelligible at the end of your next rest.

Sales Tactics

Starting at 6th level. You are granted 1 of 3 different boons specific to your patron. You are allowed to switch to another option at the end of a long rest.

Credible Crediter

As an action. You gain the ability to expend a spell slot to replenish other creatures' spell slots as long as they are within 30 feet of you, up to a combined total of level of the expended spell slot plus half your proficiency modifier rounded down. 

Persistent Peddler

The duration of your spells are doubled if they have a duration of 1 minute or higher.

You also gain the ability to gain advantage on your next attack roll a number of times equal to your proficiency modifier. This is recharged at the end of a rest

Slick Shopkeeper

You gain advantage on charisma checks to negotiate.

Limited Time Offer

Starting at 10th level. As an action you can request a "Limited Time Offer" from your patron, and until the start of your next turn, all spells cast within 30 feet of you are cast without expending any spell slots. This can only be done once per long rest.

Binding Contracts

You have mastered the art of including tedious and purposefully ambigious clauses to your contracts. Making it harder for signees to withdraw from a deal, and as a result...

Starting at 14th level. Checks to end the effects of your spells are made with disadvantage.

This does not include initial saving throws to avoid an effect.