The beagles I've come across are thick as shiteee and mad as badgers.
Is there a specific reason you want a puppy apart from the cuteness factor? Could you live with a rescue dog or one that needs re-homing? Have you researched both Spaniel and Beagle behavioural characteristics and potential health problems related to the breeds? Do they fit in with your lifestyle and time you have to dedicate to the dog?
Also are you prepared for the amount of walking you'll have to do? Note that the dog wont necessarily want to poo and pee when you want it to. Do you work at home or do you leave the house for large parts of the day? I ask this as some breeds can be a bit more needy than others.
What worries me is that you seem to be looking to minimize initial outlay. However if you get a puppy you're looking at 10 to 12 years with that dog. If you're scrimping to get one will you be looking to save on the annual jabs, other vets fees and feeding as that's where the real costs lie?
I'm not trying to talk you out of it, but to encourage you to fully understand what you're letting yourself in for.
I'm prepared for it, I've looked after other people's dogs while they've been on holiday.
I'm aware of the costs month-to-month, just that £500+ outlay is not on the cards for me right now. I've researched how much food and vets bills are and also insurance should anything serious go wrong.
As for shelter dogs, I just feel that getting a dog from a pup means you'll be able to get them used to you from the get go. I do work and I'll feel awful leaving the dog during the day, but I've talked to lots of friends and work colleagues who work all day and didn't find they have a problem.
I saw two beagles together in a shelter, but they needed to be rehomed as a pair - ain't really got the space for two dogs.