Keep the K98K. Shoot your 8mm mauser ammo.
Save your money. Haunt Pawn shops. Be patient. Save up and then think about the gun you want.
When I was a young man I bought a gun every now and then. I had a rifle, a .357 Blackhawk a .22 pistol. Now I'm an old man and I own hundreds and hundreds of guns and I enjoy (I almost said "love") them all. Enjoy and shoot your guns and as time passes buy another and then again. As time passes you will be astounded at the collection you will amass.
I have been collecting for just at 50 years and I have a wonderful collection. The secret is to strike when you see the gun you want. Sure, we don't always have the money, but save up, find a way, get a loan. I've done it all. Also as time passes your gun desires will change. I did muskets for years, then .22's, then 9mm pistols, then Civil War muskets, then a few percussion pistols, then Spanish American War rifles, then WWI rifles and pistols, then a few huntingrifles. I got into fine double barrel shotguns. Can't afford the real fancy ones, but the middle range come along and I've bough a few. A lefever, a Fox Sterlingworth, a Parker GH. 22 pistols galore.
I love old guns and the story they tell. I love shooting shotguns. I enjoy shooting old military rifles. You can too.