Plus size suit and tops for underneath - budget friendly

[NonsensicalWitch]

Can anyone recommend anywhere for the above?

I'm a size 16-18, tall apple shape and don't really suit collared shirts, but would wear tops underneath.

Any ideas much appreciated .

I'd suggest some simple shell tops, or if not overly formal environment some plain t-shirts underneath.

Thanks! I've ordered a couple of shell type tops, plain white and plain black in jersey material...I don't think that makes them too casual? They aren't tshirts, which I think might be a smidgen too casual.