I havent bought any plastic plants from pets@home ( I seem to have the touch for live plants).IMOHO silk plants generally look better than plastic ones.The main concern people have about plastic plants with Bettas is that plastic plants can have sharp edges/points than can rip the Bettas fins.
Do you live near a pets@home? if so you could always take a piece from a pair of tights (I do prefer our saying,rather than pantyhose
) or stockings etc and drag it over your choice of plants before buying them.If the material doesnt snag on the plant then it should be ok to use with a Betta.
BTW I find the price of bogwood cheaper at pets@home much cheaper than my other LFS,I dont know if you have found the same?