If your in Canada here is a nice one. http://greenhawk.com/wdItemDesc.asp?strilhID=web&strmdNumber=HOR5167&stricSKU=HOR5167
Le Mieux are great and they have matching saddle blankets and polos
Not sure where you are located, but you can buy a cheap one at a tack store and at a fabric store, but the bling by the meter (or yard) and ether sew it on by hand it use fabric glue. It’s cost effective and you can customize it with the colours you want. Good luck!
USG has some nice ones, Fun bonnets for ur nag makes custom really nice ones! Schockemohle is awesome, equifit, really you can just look them up and find some nice brands