New to tube rolling, where to purchase tubes?


I have always been more of an SS guy but now have a Monarchy DAC24 with a tube stage. (run through Ayre AX7e and GMA speakers). I am not crazy about the sound of the tube stage now (too euphonic) but imagine with the right tubes, I might find a good match for the Ayre and get a "rounder" sound. At least, reading the tube roller forums seems to indicate that might be true.

The tube stage has a pair of Phillips 6dj8s. I would like to try some different tubes to see what effect it has but would prefer not to spend a ton at first and have no idea where to buy tubes without getting ripped off.

Questions:
1. who are reputable dealers for tubes?
2. would I hear a difference if I spent $100 on a pair of older matsushitas or must I spend a bunch on vintage amperex to get a significant change in tone?

thanks.
drewh1
an update -

So I ordered 2 Matsushitas from Tubemonger and received them in 1 1/2 days! Here is some feedback on the swap.

Just so you know, I am a skeptic and don't rely on my musical memory. The nice thing about the Monarchy is that I can connect the SS and Tube outputs to different inputs on the Ayre and switch on the fly. This makes it easy to do a lot of focused comparisons.

I have to say, switching tubes pretty much accomplished exactly what I wanted. The tube section always sounded too euphonic and cluttered. It lost the separation and clarity in the upper mid and high frequencies. With the Matsushita's, all the upper frequency clarity is maintained but slightly more detailed. The big improvement was in bass and mids. Bass has more impact and mids are improved and more musical. The description I use is that the sound is "rounder" now in the tube section and "flatter" in the SS section. Since I listen to a lot of guitar, violin and acoustic instrument, this really makes a difference in my listening.

This has been the best $64 bucks I have spent in a long time - and to think I was going to go audition a Berkeley Audio DAC ($5000). All the advice was terrific and useful.

Great group of people here, thanks!
Drewh1, Its always good to hear that someone has benefitted from info received here on the Gon. I truly believe that's what this site was meant to do. Unfortunately, a lot times you get infomation here that you really don't need and can't use.
When those tubes break-in they'll sound even better.
Drew,

Eee3 is right, give those tubes say 100 hours and they will be singing even better. Congrats on a excellent improvement and not a bank breaker at that.

Roger
I have had good luck with the Tubemonger ( he had some great sounding Mullard CV2492/6922) and with Tubeworld.