My twin DDs (almost 17) have been playing travel ball since 12U (did a mild version for both 10U years as well). It depends what area you are in...cost wise. And if the team pays the coaches. And how intense the team is. Mine started at about $300/year in fees (10U) and this year is $1700 (not counting gear and hotels). Past few years we pay for travel expenses for coaches and do showcases which cost more than regular tourneys. And we have 17 on the team to spread the cost amongst ($1700 per player). Super competitive teams, like some in California, might pay more than travel expenses for their coaches (pay them to coach).
We do fundraising and can bring in thousands of dollars if we do some good stuff and have good participation (our team likes to do Coach purse bingos). That profit can get divided equally among teammates (we used to be this way when DDs were younger)...or it can be divided by how much you participate in the fundraiser (this is what our team's been doing the past 2 years...you only get credit for each bingo ticket you sell and if you have 1 parent work the bingo). The money raised gets applied as a credit to your kid's fees.
Hotels and travel. We started off going to local tourneys, most w/in an hour's drive but then a couple a year were about 2-3 hours away. Maybe a Nationals at the beach. The 10U years we did like 3-4 per summer and 1-2 in the fall. Then, at 12U, we were doing every weekend in the summer and about 4 in the fall. Once they get to HS and play HS ball they stop travel team stuff from March through early June. So we do every weekend from June 11th-ish through July. Nationals are usually the end of July. August is try-outs. And practice beginning end of August and fall tourneys begin in Sept and can go through Nov (if you are north and play local, then it usually ends when it's really cold). Then they do winter workouts.
Now mine are doing showcases (no seeding and championship play...play for college coaches to watch) and they go down to play in FL in late fall or winter. Nationals can be in Oregon or California or some such. So, airfare is added to expenses. And showcases make you use them to book hotels and might not always be the best deal that you'd pick.
Equipment...bats, helmets, gloves, batbags and cleats can be pricey. They go through them like crazy too. If a catcher that's even more gear. Pitchers may wear facemasks. There's mouth guards and sliders and this and that. Coolers, chairs for mom and dad, canopies and things to keep cool like Frogg Toggs or little fans. Then spirit wear like hoodies or jackets and sweatpants. UnderArmour for the cold. Also extra coaches like pitching coaches or conditioning or a hitting coach...all adds up.
Unsolicited advice- Don't do it thinking your DD will get a great scholarship that will save you big bucks. It's not likely because the scholarship money is very low. Very very few get full rides (DI and only the best players), one in a million. Usually, we are finding for DII, you might get like $3K. Not worth all the expense you put in playing travel ball (as you will spend way more than $12K). But do it for team sportsmanship, discipline, the love of softball, an activity for your DD to do that keeps her busy and out of trouble (especially important from about 14 on), good friendships, fitness, confidence building...