How much do these two fencing materials cost

Vinyl and high-tensile (coated, and not coated). Also, is it safe to have high-tensile wire fencing around and arena? Thanks!

I don't have the prices but I would avoid the high tensile wire. It does not have a very good visibility to it and if you have seen some of the injuiries this fencing has done, you probably would look for something else. Also, please do not use T Posts around your arena/round pens. Extremely dangerous, if you have a really well broke horse you may not forsee the reasons I have but working with young, unpredictable or green horses. well, just avoid them at all costs. Ride without a fence before doing that.

The vinyl? Are you talking vinyl rail fencing or a "tape" sort of fencing? Vinyl rail is VERY expensive. I have found that the "white 3" tape" is very visible and stays intact well with the new clips they have when applied to wooden posts. ( I use this method to section off areas within my pastures). It is quick, easy, and reusable if you want to "tear it down". That would probably be the most cost effective, safe way to go for an arena fence. You could space your posts 8 feet apart and then in the future you could start replacing the tape with wooden rail without having the work of digging more post holes and the closer the posts, the better the tape looks and stays in place. HOWEVER, if you have used the tape and have it electrified on your property, you probably won't get your horse to work on the rail, for obvious reasons. On another note, I do not recommend this fencing for property perimeters but that is not your question.