Cassette Tape

Whats available today ? Whats best and where can I find it, thanks...
EBAY! Maxell and TDK were always the brands I used back when I had a cassette deck!
There are lots of unused, still-wrapped blank cassettes in the bins at thrift stores. Buying things when no one else wants them is always the best way to go. 
If it's sealed in the package old stock doesn't matter. And frankly I'm shocked someone is still making cassette tapes! I will say those don't look well made to me, maybe its just the clear plastic but they look cheaply made.
For for the cost NOS cassettes digital is a far more affordable and better sounding medium. However, if cassettes float your boat, have at it.

Want something way batter than cassette? Buy a used Apogee Minime and Microtrack II. Total cost around $300.00. You can now make 2 track 96/24 recordings that kill cassettes all day long.
Kills them how? On paper? Digital, I’m afraid, doesn’t float my boat. Too thin, shrill, paper mache like. Yes, I know, but, but ...the noise, the wow, the flutter!
To my ears it kills them. I’ve been recording on location for almost 37 years. The first 10 was analog cassette the rest digital, with 10 years 48/16, including bit shaping and the rest high resolution. Since 2007, it has been high resolution 24 track on location with lots of rock, jazz and blue grass. In all have I probably attended well over 2000 or more concerts and recorded most of them. I do have a baseline of what real instruments sound like in a real space, both amplified and acoustic.

I say this not to toot my horn, but rather that I’m not ill informed, nor am I a Johnny come lately. Capturing real music in a real space and recreating that is something I dedicated a lot of time doing. Reel to Reel using Dolby SR is a totally different argument and it can produce some very accurate recordings but cassettes are a total compromise and really do not provide any advantage over high resolution digital.

However, if this floats your boat and to your ears it sounds better, well, that is ultimately what it is all about and have at it. And, this is coming from someone who is an analog lover. My preferred playback system is what ever turntable I have hot rodded or created. I am not dogmatic nor am I someone who will only listen to one medium. However, outside of transferring cassettes recordings to a high resolution digital file, cassettes are not one that I prefer to listen to. Hey, but that is just me.
I never said you were a Johnny come lately. But Heifetz’ violin on cassette played on an inexpensive Walkman cassette player sounds fuller, richer and more musical, more like Heiftetz’ Violin, as it were, than the very same piece on digital. More air and sweeter too. I would never argue that digital is not more accurate. 😀
Maxell xlii 90. The "S" version is "better" but usually unnecessary and not worth the extra cost, IMO. I recently sold off all of my 800+ tape collection.
I use the same cassettes I bought in early 70´s, both at home and in car. With a few exceptions all of them are as good as back in the day, mechanically and in sound quality. I buy new and vintage cassette tapes off eBay. Never liked digital´s dull and edgy sound.
You can get blank audio cassette tapes on Amazon. Most of them in 5-packs, 8-packs, 10-packs, etc. come to about $1.25 to $1.50 per cassette.

Absolutely correct, Amazon has some pretty darn good deals on cassette tapes of all varieties.
Good place to look imho
I still use cassettes. I record some of my rare jazz and classical records and play them in my car (2005 Lexus LS430) on the Mark Levinson stereo system. All analog, ya know. :-)

For top quality tapes, check out the thrift stores. Top of the line, used 90 minute Maxell and TDK tapes are available for as low as twenty five cents each. Use a pen or pencil to be sure they turn freely. Use a quality VCR tape eraser, rewind to the start, and you’re ready to go.

No no no, buy only sealed Maxell XLII S 90 for type II and Maxell MX-S 90 for type IV metal. Get them on ebay from people with excellent feedback. I never had problems with sealed tapes. Look at the pictures, the wrapper should not be warped much because if it is they might've been exposed to heat. If they were stored near magnetic fields the first time you record on them they might sound dull. No worries, record the second time and it should be fine, just a bit more noise. Or throw them away.
Thanks for all the replys, I got my Maxell XL II in today, I can't help wonder how old they are, anyway to find out ?
I used to record stuff on a last generation Teac 8 track studio recorder…DBX, double speed…I recorded the title music for a TV show, mixed it to my Nakamichi BX300, and dumped it onto a SONY Mini Disc for the TV studio's digital needs. Did my recordings sound great? Well of course they did! Now I'm like everybody else with MAC based blah blah and my 8 track and NAK languish in their boxes in the basement. Now I mix concerts and record them onto tiny digital gizmos with no charm to them at all…except the music part.
I still listen to pre-recorded cassette tapes. But it never beats a properly mastered CD played back through a good DAC.