Do you recommend any basic spd pedals for Indoor training(Zwift trainer)? The cost of the spd pedals I keep seeing are over $100. I was going to try to buy a cheaper set for my "rainy" day bike rides.

dont forget craigs list. those peddals near me are 20 bucks.

Is Delta cheaper?

Delta is a mostly outdated cleat, no one in cycling is really making pedals for them anymore as they have moved to KEO or SPD-SL or one of the many other options. In this case the OP was asking about 2 bolt systems specifically SPD which in the case of most shoes is not cross compatible. There are some lower cost road style shoes which can fit both but less common in cycling.

OK. I still see plenty of Deltas being used at my cycling classes. I like the sturdy way it holds the foot.

They some how got stuck with spin classes but aren't used in cycling anymore. Look moved on to Keo quite a while ago which is just an upgraded version of the Delta with better walkability and functionality

There are plenty of them starting around $35 on Amazon.

Or just get some legitimate ones and save yourself the problems of knockoffs and fakes and just general cheap stuff.