Some quests are, in my opinion, not worth completing due to their lack of a profit or give something that cannot be easily converted for MP, or I don't have a ton of experience with. Below is a list of quests I believe fall under this category and thus will not be discussed in this blog:

Aquarium
Computer Repair
Drew
Eleka Prison
Hump Racing
Knutt House
Knutt Knight
Microwave
Personal Trainer
Robot Repair
Sewer Monster
Shusan
Slater Stalker
Sumo Sally
Talon
Travis Truck


Borak's Brew
Asks for: 1 item
Prize(s): MP and sometimes cooking items
This is a quest I recently got into, as it gives out a relatively large amount of MP (2-6k+). The cooking items it gives out are not super profitable (currently 200mp-2k each), but the MP makes this quest worthwhile.
Recommended max amount to spend: 4k

Candy Tree
Asks for: 1-3 candy/chocolate items
Prize(s): MP, occasionally candy fruit and very rarely a Chocolate Costume
A great quest for newbies, generally because the items asked for, if in stock at the chocolate shop, are cheap. Note that there are some expensive/rare chocolates/candies that can be asked for, but generally if the item(s) asked for is in stock it will be profitable.
Recommended max amount to spend: 3k

Cosmonaut
Asks for: 1 item from shops, must be restocked
Prize(s): MP, occasionally Dips, rarely Enchanted Dips
I used to do this quest a ton, but it gives out such little MP (200-5k) in my opinion it's not worth doing regularly. Dips/enchanted dips can be worth quite a bit (10-100k+) so I'll start a quest occasionally, but as of recent a lot of items have not been in stock anyway so they've been hard to complete.
Recommended max amount to spend: 2k, as long as the item is in stock

Farming
Asks for: 1-3 items from shops
Prize(s): MP and occasionally balls of yarn
This is a quest that I do regularly. The amount of MP you get from this quest is decent (1-2k per play), however the balls of yarn can be profitable. Basic colors of yarn can be ~10k, but the rarer ones can be sold for 500k+. I've received a few balls of yarn that are only given out from goals, which can be quite profitable as most of those are UB.
Recommended max amount to spend: 3k

Garage
Asks for: 1-3 car parts
Prize: MP
I regularly restock from the car p