You don't even need that. Phones like the LG Fortune, which I own and works totally fine, can be bought for $25 new and out the door, no contract, at mainstream retailers like Best Buy.
I also have a moto e4 which I'm using to type this. I think it cost me about $65. (I also have a variety of iDevices and flagship phones for testing stuff I write)
We are in the age of adequate, super cheap phones that aren't awful. I have the option of, but choose not to place my sim card in one of more expensive and flashy devices I own because I'd rather have the thing I carry with me be a "worthless commodity" that could get lost without my caring at all.
Last time my phone broke I just swapped the sim card that day, not caring in the slightest. This is a liberating experience.
You can also do this with prescription glasses - you can pay under $7 a pair online. Anti-scratch, investment preserving upgrades and the feeling of preciousness are all gone. Not having to emotionally invest in things is wonderful.
It's actually not too bad, even on phones without "easily" replaceable batteries.
Speaking for the OnePlus One and Nexus 5 the procedure is pretty straight forward: pop it open using plastic trim tools (which are often sold with batteries) disconnect the ribbon cable and pry the battery off any adhesive. Drop the new one in, reconnect it and snap it back together and you're done.
Depends on the phone I guess, but the whole thing takes maybe 15 minutes.
eBay is your friend, you can get batteries for ancient phones like the Samsung Intercept for $4 still, brand new. Luckily for us, batteries are a highly commodified component, you can replace the cells yourself with minimal effort if you so choose.
When I'm feeling like an uber-cheapskate I rebuild laptop batteries, recycling the failed cells and replacing them with good cells from other batteries.
