If you have horizontal space to put up a dipole 5 to 15m above ground, this could be an option depending upon your needs, or you may already have a dipole that can be used on 30m without having realized it.
There are different types of horizontal dipole aerials (ANTs) to consider as options, in both cases The dipole is fed in the middle with each leg being the same length.
ONE: a 50 Ohm coax-fed dipole of a half wavelength, or, an 80m band dipole which is 3 half wave lengths near 30m and thus easily brought to resonance via an AMU (ATU) ANT matching unit/tuner. Each leg is around 7.5m long for the half wave dipole (trim or twist back for resonance in situ). No AMU is needed if it is cut as a half wave on 30mb. You'll need to check azimuth patterns though as I suspect this may become a multi lobe pattern on 30m which may or not be what you want.
TWO: if a 300-600 ohm twin balanced line or open feed line (you can purchase these or make them yourself) instead of coax, then there is the benefit of multi band use, and this dipole is then known as the "doublet" ANT. I'll talk more on the doublet option below.
No matter which choice you make, (single) band 50 ohm (it may also work at 29FM band, or with a tuner there), or multi-band doublet with balanced (open) feed line, the radiation pattern will be similar: if you have it horizontal at 5-8m above the ground it will not be great for DX as the take-off angle will be high, but this will work well for closer in or mid range regional contacts.
If you can place the dipole or doublet 10m or higher you will start to make easier DX contacts, especially if you can get it 15m above the ground. When low the directivity will not be pronounced but from around 10m above ground and higher you'll get best signals at right angles (broadside) to the ANT, and nulls (attenuated signals) off the ends.
If feeding with balanced line (maybe 300 to 600 Ohm impedance or so) then you will need a BALUN transformer, at the end of the feedline. I will place some links to useful information about doublets, feeders, and lengths to avoid, at the end of this post.
Note that an advantage of the doublet is that it does not need to be cut to a half wavelength. For 30m anything about around 0.4 wavelength, should work efficiently, meaning that if your horizontal space is at a premium you can cut it to say total 2 X 5 = 10m top length.
Another option in case you don't have the space for around 15m horizontal is to drop the ends of the wires down vertically, like pig tails. This will keep the useful radiation on the horizontal section of the doublet rather than using the top section of the feedline to radiate.
Remember that the ends of dipoles aren't useful for radiation, are low current, but high voltage - do not touch and keep out of reach. Absolutely fine if you have your doublet up say 10m or so but don't have 15m horizontal space. However, I'd not make the pig tail ends too long, though up to a few metres should be fine. Perhaps someone can model this and give feedback in that regard.
I've used several doublets at 10m above the ground on 30mb at various locations, one where I had the ends dropping down 1.5m at each end, and always with good results for DX broadside to the doublet. Certainly a few more metres in height would have made it even better.
A 44ft (13.4m) doublet provides a consistent radiation pattern on higher bands such as 10m, 12m, (search for Cebik W4RNL on the 44ft doublet) - so on those bands it does not have multiple lobes as happens otherwise and keeps its broadside radiation pattern on higher bands. Note that this length will be fine for 30m and even work on 40m.
You can make a very strong doublet out of two equal lengths of wire without any joint at the centre, which in my experience is a problematic weak point that breaks easily if not done well, by doing it as seen in these photos (I'm not suggesting to buy this but make it yourself, see the photos, I've done it this way and it is very nice, strong and cannot go wrong:) https://www.trueladderline.com/80-10-meter-w7fg-true-ladder-line-open-wire-fed-dipole-125-dipole-50-feedline/
Links to further useful information:
Matching Open Wire Fed Antennas
https://www.dj0ip.de/open-wire-fed-ant/matching-o-w-f-antennas/matching-solutions/
Recommended Lengths:
https://www.dj0ip.de/open-wire-fed-ant/recommended-lengths/
Charts of Feedline Lengths:
https://www.dj0ip.de/open-wire-fed-ant/charts-of-lengths/
Open Wire Fed #Antenna Center Insulator:
https://www.dj0ip.de/open-wire-fed-ant/center-insulator/
OCF Dipole (Windom)
https://www.dj0ip.de/off-center-fed-dipole/
https://www.dj0ip.de/off-center-fed-dipole/80m-ocf/
Doublet Antenna
http://www.webclass.org/k5ijb/antennas/All-Band-Doublet.htm
Matching open wire: https://www.dj0ip.de/open-wire-fed-ant/matching-o-w-f-antennas/matching-solutions/
https://www.dj0ip.de/open-wire-fed-ant/
Centre piece home brew: https://www.dj0ip.de/open-wire-fed-ant/center-insulator/
A circuit that includes my switchable balun can be seen at:
http://www.alg.myzen.co.uk/radio/qrp/port_atu.htm