I have a Fender amp that give me unbeatable clean tones, a Blackstar that's giving me awesome Heavy tones with new tubes and I want to use both.
I need a pedal that can switch from the Fender cleans to the Blackstar heavy distorted channel. I need something with buffer, because I don't want to lose any of the tone.
Max money to spend is 250 bucks, no more. I need something good for that kind of money or less. Any help would be apreciated.

I'd look at the Radial Switchbone. It might push your budget a little, but I think it's a step up from the ABY boxes made by Morley/etc. Radial makes quality stuff, so you could also probably find it cheap used.

Not sure how much your 250 Xuxuexorxo bucks is worth but I second what smooth55 said. I've had more than a few Radial products, still have a couple, and everything is top quality!

If you are doing A/B only, there's no need for a buffer.
What more important is avoiding ground loops when you set up an a/b rig.
I recommend a A/B-box like the mini A/B from Loop-Master
Those are identical to those Eric Johnson is using. Also pretty easy to make yourself, I've made a few over the years. No tone loss, no ground loops.

I recommend building your own for $20.00

You don't need power, unless you want an LED indicator.
3 mono jacks
22 gauge wire
3PDT footswitch
A small enclosure

And no, you don't need it buffered.

Indeed and if wired correctly there will be no ground loop issues.
I can't post links or pictures yet, so anyone who wants a picture of that wiring have to PM me...