Well im not an expert, but I have been shooting all my life and I own several firearms, so I know that gun advice may be biased and not reflect the most economical choice. Since I get a chance to be "Walther biased"
I will take it and say get a P99. I love mine, have never had a problem with it, and it comes in an awesome version with an O.D. green frame and black slide. A 9mm is probably the most economical cartridge for you because it sounds to me that youre relatively new to handguns and I know it would be better for you to be able to practice practice practice and not let cost or availability of ammunition get in the way. Competence with a 9mm is 1000x better than incompetence with any other round (hell I carry a .380 and feel perfectly comfortable). Now in keeping with "economical" advice, all the guns you listed are fine handguns and you can probably get them cheaper than the P99. That being said you should also look at Glocks, I personally hate them because of the way they look and feel but they are fine guns with a huge potential for customization, they are extremely durable, and as a 1st gun it wouldnt be a bad choice. You should feel out all your choices before you decide. It may be the best gun out there but if you dont like to shoot it then its useless.